Hello everyone, I'm new here

No betta yet, as I need to get the stuff first. I'm having a few issues, though.
First being that I can't seem to find an aquarium. I can find them of course, but never one that would work for me.
I wanted to get a five gallon, rectangular shaped instead of bowed or hexagonal or whatever, so I started looking for those online at places like petsmart/petco. The cheapest I could find was part of a kit for $30, only the rest of the kit (which was just the hood, filter, and light) would be unusable to me, according to the reviews, because the light burns out quick and the filter is too strong for a betta.
So I kept looking, and I couldn't find any 5 gallons that were
just the tank, that I could buy a hood for later.
I found a 2.5 gallon rectangle aquarium for $14, but I
really don't want to go below 5 gallons. Not to mention they sell 10 gallons for the exact same price. I would just get a 10 gallon, but I don't have room for it. The betta would have to be kept in my room, and since I already have a mouse and a hamster, plus the normal things like a tv and radio, I only have the table-space for a 5 gallon or less. Except I don't want to go less.
Am I asking too much to find a rectangle shaped 5 gallon, with a hood that actually works? Am I just going to have to bite the bullet and get the $30, and just not use the attached light/filter?
I'd appreciate any help/advice.