Potty Training Problems

My son will be 3 in November, but I am eager to get him potty trained. Listed are reasons why he should be.

1. Diapers cost too much money! His size diaper runs about $.29 a piece.
2. He pulls out all his wipes out of the box.
3. He's almost 3.

He has been good about telling me he's wet or dirty. I wonder if anyone has some good tips to help move this along. I am going to invest some money on a potty chair. I bought him one that he was not so crazy about. It even scared him because it looked like a monstrosity. I think this effort will save me some money too, because diapers are so expensive. I bought him some Spider Man underwear and he responded well to wear them. I bought him some training pants and he ran like the wind. Does anyone have any suggestions? How much do you all spend on diapers? I get $1.00 coupons for diapers but $1.00 does not make a dent in the total price of a box of diapers. I tried to go on diapers.com but that too is expensive.