Sure, Ti 4200 is a very good card.

Are you basing it being 8x on the ebay description? To me it sounds like a generic copy-pasted text, considering that the sticker on the card says 128 MB and also the title of the listing, yet the description says 64 MB. It might be a 4x. (EDIT: it has to be, since XFX's 8x cards say 8x on the sticker, and this doesn't.)
However, it still won't make a difference; 4x and 8x are compatible.

No idea about the price and driver.

P.S.

AFAIK the part about "Sorry, No Returns" is only for buyer's-remorse, when the item is fine but the buyer changes mind. A faulty or wrongly listed item can still be returned.

Hi, First off I know very little about old hardware, so please bear with me.
- Not another one...

Is this variant of the card any good? I know there were bad variants of cards back in the day, like SE models, but is this one ok?
- It's not an SE, and XFX was a decent brand. It's a good foundation.

That's $100 CAD I paid for it. Did I get ripped off?
- Average price, nothing to brag about.

What driver version should I use with this card?
- Depends on the operating system, I assume it's W98SE so 45.23 and earlier is probably best.

Also, it's going to be paired with an AMD Athlon XP 2500+ in an Asus A7V400-MX motherboard. I think the motherboard only has a 4x slot, but I don't think that will be an issue right?
- Correct, the card supports 4x and will work, but we don't know anything other than what you tell us so there might be issues.

XFX 8X Ti4200 cards are coded beginning PVT28A, rather than PVT25A for the 4X cards (sellers text is straight lift from the TechPowerUp Ti 4200-8X page)