Best thing to use

Jig saw.

Dremel Trio

for 6x9 go with a jig saw....for sub cut outs use a router and the jig that has different sizes

Yep, a jig saw can be had for very little..But for an all around tool to do cut outs on doors /wood/grinding ect for detail...Dremel or my favorite RotoZip

Dremel Trio

Click to expand...

Uhh, Dremels **** at cutting through wood. For the price of what one costs you could get a router (which I don't recommend unless you plan to make a bunch of boxes) which would be 10x better. The Rotozip is better (but not much), unless you plan on using either the Rotozip or Dremel for other uses, they wouldn't be a very good investment. Plus the bits are very lame and small. A jig saw works fine. It's cheap, the blades are cheap, and it does the job.

you can get a brand new jigsaw for $20, If you plan to do round cuts a lot you should get a router and jig.