need affordable, high-gloss, black background business card

I guess you are in the US, so we wouldn't be able to help you as we do not ship our business cards internationally.
I suggest you look at a few different options, such as gloss lamination to improve the card shine.
You mentioned 1K business cards for 100 bucks. Does this price include embossing?? If so I'd go for it as it's a very good price!
Business card embossing, hot foiling, die cutting and similar enhancements are specialist items. Very few printers will offer these services and when they do, they will rightly charge for that.
Have a look around but I would not expect anything less than $100 if you decide to go for special business card printing.

10th is right - the raised lettering (NOT the gloss background) is the hang-up for pricing. You can go with embossing (where the paper is actually "raised" and the ink is on top of the raised area) or you can go with thermographed (which is ink containing a special powder which raises the ink off the paper when heated), but either one is considered a special job (more or less) and the price you quoted is reasonable. That's also why they need to print a minimum of 1000 - because it's not cost effective to run 100 or 200. If you're willing to give up the raised lettering you can get full color digital printing for next to nothing from the overnight printers on the web. There are places that will toss in full UV coating for FREE(!!!), which will make that black background (and everything else) shine like plastic. (which is environmentally UNfriendly, btw - UV coating takes forever to break down in the environment). They also print the backside for a ridiculously low price ($5?) because they're ganging them up and it doesn't matter to them if both sides are printed - they have to run them anyway.

Yeah I've never heard of someone wanting both a UV coated back and thermography for the front. Most people go with a UV coating nowadays, I'm not a big fan of raised lettering. If you're talking about embossing for $100 I would go for it, although it seems silly to me to spend that much for only 100 cards. You could probably get 1,000 cards for close to the same price. I know you said you may change information, so I would go with something simple to begin with if you think there is going to be information changes on the card.

I get my cards printed at godlikeprinting.com. They only charge $49 for 1,000 business cards printed and shipped to you door -- Free shipping. (For Matte or UV Coating)

Wow, $49 dollars. I just printed mine at wymprint.com for $24 dollars and paid $7.52 for shipping. 1000 Gorgeous cards 14pt, 4:4, and UV both sides. And the black, is really black. I am sure there is no other place to compete with them, quality, service, or price wise.

Gang shops that do thermography will usually publish price lists showing a 100% markup over what the print broker actually pays them. For the record, my thermographer's published retail starting price for 500 cards on plain white stock with either black, Reflex or red thermography is $25. (I pay $12.50. I could give the client a discount over the published price and still make a profit.) Prices go up from there, depending on how many colors you want, whether they are standard or special Pantone matches, and the quality of the paper stock. Although there are ways around this, Thermography doesn't lend itself to two-sided printing.

Better search on Google for printing your business cards and lot of websites allow you to download their free business card templates

Try vistaprint.com- you can get 250 for about 9 bucks. You can get glossy finish but no raised type.