What kind of fish do you like? That's where I'd suggest you start. Tetras, WC
minnows, Betta's are all good starter fish IMO
. If you first decide what you want, then look at tanks that are appropriate for that species when they're adult size (ie don't get a 10g tank for a goldfish that needs 20g minimum), you'll have a good first tank.
Here's a kit that I have and it's my favorite, the only thing I added was a heater. I posted a UK link, but it should be available no matter what country you're in.
Fluval EBI Nano Shrimp Habitat 30L - 10511 - AquariumSuperstore - The UK's Leading Online Aquatic Retailer
This is a shrimp kit and they're a ton of fun to watch, but mine is a Betta community tank with Cardinal Tetras and plants, here's a link to my build thread with info that might help. Fluval has the same thing in a planted version call the Flora kit.
Community Tank: Fluval EBI with Betta as centerpiece
Hope this helps!