I have 2 rats at the current time. Freddy and Eddie, They are about 4 months old, and are the best of friends, At one time we had 21 male rats, That lived in a huge cage.
Rats can be lots of fun, They are very Smart. I had some rats that would come to there name when you said it. They love to come out for play time, but if you had a big enough cage they are happy to be in there too. Its always a good idea to have at lest two rats to keep each other company when your away. Plus when they are young they love to play fight with each other. Its always fun to watch them play
I don’t think it cost much to feed rats. We buy a small bag of rat food that cost about $10 a month, Then we feed them table scraps for treats since rats have a big verity of food they are a load to eat.
The only bad thing about rats is the only live to be 2 to 3 years, Some have lived longer but doesn’t happen very often. Rats get repository infections easy but a vet visit well give some medication that well help.
I have this site http://www.petratscanada.com/ it has a of good information about pet rats.