i understand what you mean with the money thing lol. i'm 20, live on my own (with the exception of 4 other house mates), and i agree it is hard to start the tank with a money issue
***I'd say keep fish in pairs of 3 or so, and try to stay away from guppies, they are pretty fish under the right lighting, but they are always picked on by other fish. I've always said that neon tetras are pretty and they are easy to keep. try just mixing a few community fish at a time.
i don't know what types of ornaments you have in your tank, so I'm just gonna throw this in just cause. note to all psycho ppl out there that jump to the gun and flame, this is just put in for random advice, so don't bite my head off!!!! i say go out and get plants, make sure that its suitable for the lighting you have. different types of bulbs are meant for different set-ups. just ask he store person for advice. just asking for advice on how many fish to buy is a bad idea, anything to make $$$ right? some plants need certain light types, unless you get plastic. next go get maybe some wood that will stay at the bottom. certain fish like wood and stick near it and others just like plants, and some like rocks. the different types are so that your fish will be happy and comfy. the wood may turn your water to a tea color but a lot of ppl say that the wood has a calming effect on the fish. have colorful stones in the bottom, try to stay away from bright neon colors, it stresses out the fish, try to stay with colors that are natural, it will look more natural to see the fish in their original sort of habitat. ornaments don't have to be from the pet store. i put a martini glass in mine in the corner and put some clean marbles in it. of course, when you use stuff from around the house, make sure its clean and don't use soap or any kind of cleaner. you want it to be clean though so i just got new glasses, soaked it alternately in got then cold water then hot and then cold again. i only do this with glass because you can hardly boil glass on the stove. rocks and such i suggest boiling it on the stove then rinsing it in cold water. people argue that you should do one or the other, so obviously they do it so it cant be harmful, so why not do both? bubblers are fun in the tank too. the motor for it is cheep for the size tank you have. just get a connector hose for it and if you want a bubbler end for it. i had just taken a very long hose piece, sealed the end and poked holes through it then put it under the gravel at the bottom of the tank, coming up the corner of the tank. it saved me money on the bubbler pieces and it looks nice when its coming through the ground as well as i was able to make designs through the tank with it. when you have a bubbler it provides oxygen in the water and will make your fish healthy. as i said earlier though, you don't have to follow this, its just here for advice. you add what you like and arrange it to your tastes. i have no clue on how much you know, so i just threw this out there for ya just in case.
those things will make your fish comfy, happy, calm and will make your tank look nice with color and provide a natural habitat for your fish to live in, allowing them to act as they should
a tip on what not to do though, is do not put store bought seashells in your tank. the way that they are cleaned is harmful to the fish and may kill them. shells from the beach that are cleaned right are ok though.
I know the tank is small but I have 3 already and would really like to have a bigger one but I'm 21 and still live with the parentals so no such luck lol so can someone suggest a stocking list that will add colour to my bland tank? 
