if you BYO, it will cost probably more. Lets just say, one CD-RW Drive is around $50.00 thats $100 already right there. Then casing, PCB , TIME (does it work ? ah! crap gotta do it again) ........just don't spend your allowance for 5 months and just get one (headache free).
Do some extra chores like clean Dads car, clean the garage cut the lawn etc. so they give you a little more $$$.