Absolutely DON'T be ripped off by that Betta kit, I got it for my birthday and there's literally nothing usable in it. I had to go out and buy new conditioner, different food, EVERYTHING. Why don't you check out the TopFin 2gal? It's only $9 more expensive than the kit and the difference is absolutely phenomenal. Adding in food, a heater, a thermometer, new conditioner, and a little fishiecave, I probably spent a total of $50 on my setup. I'm sure you could do better if you shopped around for sales stuff, I was just kind of in a hurry because my dad had gone ahead and put a betta in the tank and I wanted to move him to something he'd look less miserable in as quickly as possible. Since you're going to have to get a heater ANYWAY unless you live in someplace like Texas or Florida where room temp is going to be 75-80 normally, it's honestly just less of a pain to go ahead and get the 2gal tank because it's almost impossible to find a decent heater for the .5gal that comes in that kit.
In summary, through personal experience, my problems with that kit were:
1. tank is MUCH too small for a happy Betta, also necessitated way too many water changes.
2. couldn't find a decent heater for a tank that small
3. aquatic plant is icky looking and has very hard leaves, neither of my Bettas were very keen on it
4. it came with flake food, which neither one of my Bettas would eat, and the PetSmart employee I talked to actually advised against using, ever, on the grounds that the PetSmart Bettas (at least in my area) are fed pellets. it's also harder to regulate flake food.
So in short, the TopFin 2gal is DEFINITELY worth the extra $9. (seems to be a bit less on the website than at the store, but they may be making it up in the shipping) It also fits really well on my desk, was easy to assemble, and is really easy to do water changes with. You can check it out here
Edit: Forgot to mention that with the size of the bottle of conditioner and the container of pellets I bought, I probably won't have to buy food/conditioner for at least six months, possibly longer.