Need lumber advice

hi, please pardon my noobness

i wish to build a high clearance shelf for my desk,

i am way too new at stuff like this, i have no real tools other than screwdrivers and tape measure, but i am willing to maybe go out and buy some cheap but decent tools(dont know if i should have mixed those last words ^_^ ).

i would like to do most of the work myself, but i think i would be better off having the shelf cut out for me at the store(if possible)

the closest DIY store to me that i can get to is a Home Depot.

will they cut the wood for me?.

other things regarding this project, is there a way to clamp the stands for the shelf to the desk without drilling into it?

anyone care to quote me average prices for some decent lumber?

i am looking at 5 feet long by 3 feet wide by 2 feet tall

the goal for the shelf is to have a place for my printer and some scale aircraft models