Printing Primer? Ordering Prints?

[Pose]

I've been messing around with photography for a while now, and out of the 70+ rolls of film in my "decent" bag, I have about 35 images I'd like to have printed, in good quality, but I'm not sure where to start. I have the 35mm negatives, which I got developed at walmart, wolf camera, or walgreens (mistake?), and the images on a CD. Do I just find a pro lab, go in, hand them the CD, or negatives, and tell them how many I want printed, and in what size? I'm not sure how it works at all.

The sizes I'd like are 5"x7", and 8"x10". For future reference, is there anything I should do specifcally to prepare for large prints, such as a certain type of film? I was also wondering if it is best to have them printed in bulk, or just make a custom order each time you get an inquiry?

One last thing, I was contemplating buying a printer, the Epson 2200. In the long run, would this be a better choice for business?

Thanks for any help.