Hi amazingbiologirl
Do you mean a mixed tropical community tank? If so, if you can put together a tank and the equipment to run it, you will find a wonderful assortment of fish to go in it for not very much money.
To make such a tank, I recommend getting the biggest tank you can afford. Since you already keep fish, I'm pretty sure you know why.

Then think about it in terms of the top part, the middle and the bottom. You will want to get fish that inhabit all of them.
Then, think about the different shapes and sizes and colors of fish (small or smallish for a not-too-big tank) that are available. For example, long skinny kuhli loaches, short chunky cory cats, elegant dwarf gouramis. Perhaps you might like a small school of pink glowlight, or cardinal tetras for color and a few glass catfish for something unique. These are all egglaying fish, but if you want to add livebearers, platys are great for color and guppies are active and attention getting little things.
There are so many possibilities that the list of not-to-expensive fish could go on and on. I hope I have given you something to start thinking about and that it will give you at least an idea or two to start planning with.
