Strange lump

I came home today and was petting my 6 year old, male domestic long hair/maine coon mix (Pepe) and I noticed there was a bump on the side of his body (probably the size of one of those plastic bouncey balls). I sifted through his fur and there isn't a cut or bruise or anything associated with this bump, it seems to be under the skin. When I touch it or rub it it doesn't seem to bother him or hurt. I'm a new cat owner, only adopted around 3 months ago so I'm not sure if this is normal for cats to get or if this is something serious I should get checked out. I've always received great feedback and helpful answers to my questions from this site so I figured I would come back to you all and ask your advice. Please help!!!!

I bet Pepe has a fatty lipoma. They are more rare on cats than dogs, but it is possible. Pipsqueak, my cat, has one. The vet can aspirate some fluid out of the lump and look at the contents under a microscope. If the fluid is real greasy and whiteish clear - it is most likely a lipoma. A totally benign tumor. Of course, I would take Pepe into the vet to ease your mind.

Did he have any vaccinations recently?

It makes me feel better that this may be something that is not very serious. Do you know how much it costs to have a vet look at this lump if it is a lipoma?

As far as shots go I do not believe so. From his documentation, he had all of his shots about 1 year ago or earlier this year. Since he has been with us in July he had basically just stayed in door here. Normal hair balls here and there. I believe he is due for all of his shots in 2013.