No need for Cycle...it's a snake oil product. If you want to add bacteria to the tank and try to get an "instant biofilter" then try BioSpira. Most people have had great luck with it.
However I would suggest just doing what is called a "fishless cycle." That is where you get a bottle of plain ammonia (not the sort with any perfumes or anything...the ingredients should just be water and ammonia) and add a certain amount to the tank regularly while testing to see if the bacteria is acting.
If you search around this forum or google you're sure to find a good article on how to do a fishless cycle. This way (it usually takes a little less then a month) when you add fish to the tank, it's already prepared for them and they won't have to suffer through ammonia and nitrite.
Now the number of fish you'll keep depends on the fish. A five gallon can usually house between 2 and 6 smaller fish safely. There are sooo many to choose from so I'll just throw out a few personal favorites in various combinations that would likely work in a small tank. The basic ingredients are one small-tank suitable non-schooling fish and a small school of small schooling fish or small catfish:
A betta, two small corys and two otocinclus. (My current setup in a five gallon is a male betta, two corys, an oto and a bamboo shrimp.)
A betta, four small schooling fish like neon tetras, white cloud minnows or harlequin rasboras. (Avoid danios they can nip a betta)
A honey gourami, a cherry barb and two small corys or otocinclus.
Those are just some examples. You can mix and match those except for putting in two bettas or two gouramis or a gourami and a betta. Remember to stay only with the tiny gouramis like the honey gouramis. Others are too big for that tank. I'm rooting for the betta though, as they do well in small tanks and are relatively hardy and very attractive.
