@Michael-Angelo-Go is it possible you're overthinking the price of the watermark/no watermark? I don't know that many people will want to steal your work, and even then, you have the legal/moral high ground on that.
But perhaps others can offer their two cents as well.
@Michael-Angelo-Go I'm confused about the term "watermark". A watermark is usually semi-transparent text overlaying the entire image in a deliberately garish way to deter art thieves.
It would be incredibly insulting and inappropriate to give this to a paying customer! But it doesn't sound like that's what you're doing: it seems you're talking about your signature. A signature is not the same as a watermark. It's an artistic choice and it's supposed to be a good thing to have the art signed by the artist. Your signature is maybe a bit big (slightly smaller would be more tasteful) but it's not really a watermark and referencing to it as such is depicting it in a really negative light. Giving the option for people to PAY to remove it depicts it in even more of a negative light.
I'm also a bit confused by just HOW MUCH you charge for removing it. It's so expensive that it sounds like that would be the price for a commercial license or some sort of commercial rights. I've never really heard of people paying to have the artist remove their signature, so it may confuse people into believing they purchased commercial rights.
Ultimately if I was a customer this whole thing would turn me off and leave a bad taste in my mouth. I wouldn't have thought twice about the signature before I saw the option for removing it. It makes it sound like you're trying to slap a watermark on a product people are paying for and having them pay an enormous amount of money just for removing it.
Like @lpetiti said, using your work for logos or other things would be illegal to begin with. Building in additional deterrents into your offer just makes the offer less appealing and more confusing. At some point in order to sell your work online, you have to accept that there are inherent risks that you can always 100% protect yourself from. You have to accept that at some point, some people may break the law and steal your designs, and then you'll have to defend your rights and get it taken down. And that you can let this fear stop you from making a living off your own work, or you can decide to enjoy your own work and sell it however you want to sell it, however is most appealing for your customers, despite possible risks.
I had to wrestle with this idea when I opened a shop selling digital only products. I send people high resolution files of my work, with only their word that they'll respect my rules and not use them in any commercial way. Yes it would be easy for someone to buy my product, take the file and turn around and make prints of my art and sell it. But will I let that stop me from selling my own damn art however I want to sell it?
If I was searching for commission work on etsy, the price jump would only confuse me and ultimately lead me to a different seller. The price for removing the watermark (ie., signature) is fitting for someone with a lot of disposable income, but ultimately that's not necessary who shops Etsy. I've only seen those prices on items like metal work, or high quality cosplay items.
At some point, if we want to sell our work, we have to have some sort of "blind trust" as it were and then deal with any outcomes that arise, if someone tries claiming our work .
Besides I don't know how much that signature protects your work. It doesn't cover the animal. If someone wanted to use it they'd likely remove the whole background and signature with it, right?
vanessastoilova.com
instagram.com/vanessa.stoilova/
Check out my Youtube channel for tips on how to start your career in illustration! www.youtube.com/c/ArtBusinesswithNess
Congratulations on your shop! 
I kinda agree though, the watermark does seem to hurt the image a bit. Maybe make it more subtle or remove altogether?
@NessIllustration Okay, I just had a lot of anxiety when I went into doing this. I need to have a lot more confidence obviously. I just removed the watermark/n option, so when they receive the final product it won't have a watermark or signature.
Finis Coronat Opus
Instagram: www.instagram.com/madgcartoons/
Behance: www.behance.net/madgcartoons
Website: https://michaelangelodgo.wixsite.com/madgcartoons
@Michael-Angelo-Go A signature is fine. I as a customer would want the signature, I have plenty of art from various conventions that is unsigned and I have no idea who the art belongs to! Yours is a tad overwhelming, though.
I think everyone was confused and they didn't see that your images have a tiny watermark on them as well as the signature, the watermark certainly is insulting to the customer.
Pricing your work is difficult, I agree that the 700+ for these portraits is very hard to get behind. I assume these are digital and are delivered digitally? How long do they take you? Judging by your other work, as well as the occasional mirroring, and all the portraits being in relatively the same pose, I wouldn't guess too long. These are things you should consider when pricing your work.
If I'm mistaken and you are painting these, or printing them and delivering certainly factor those costs in!
@jakecrowe Oh wow you're right, looking closer I just noticed that there is indeed a small watermark (a website?) on the animal itself. @Michael-Angelo-Go that's a big no-no. You don't give a watermarked finished product to a paying customer!
@Michael-Angelo-Go amazing congrats!!!
@Michael-Angelo-Go Well done on getting your shop up and running. Ness is right about watermarks needing to cover the whole image. It's easy to remove them. Here's an example from the pic you posted. I just used the lasso and content aware button and used healing tool on the back paw. So that was the computer doing all the work. Took under a minute.
I personally wouldn't bother with watermarks unless selling for stock images. They distract the eye from the image underneath. Signatures are best used on limited edition artwork or for selling originals (signed in pencil or paint). If it's an open edition I wouldn't sign it.
Plus a digital signature can be lifted off and then placed on other art to pretend its made by you.
For a digital signature, make sure it's not the same signature you sign cheques or credit cards with! 
@Michael-Angelo-Go is it possible you're overthinking the price of the watermark/no watermark? I don't know that many people will want to steal your work, and even then, you have the legal/moral high ground on that.
But perhaps others can offer their two cents as well.
