Ju Ev -
I wouldn't buy another suit for the training. You get fitted for your uniform on the first day of induction (sunday) and you don't have to wear it until you start grooming. The day of grooming varies as some weeks there are a lot of abinitios starting, so you may get grooming 2-5 days after starting induction. You are also out of uniform for your day of ditching, by which stage you can easily get it drycleaned in time. I got by with a blazer, pants and skirt, and haven't worn them since I did the ditching session over a year ago.
Regarding the laptop I'd wait until you're flying as you don't really need one during college and you can go to an internet cafe for emails.