It can be done. You need to know if your glass (where you are drilling) is tempered or not. Some manufacturers even drill then temper the glass. No
LFS that I know of will try to drill tempered glass. It's just a disaster waiting to happen.
My
LFS charges 10 bucks a hole. That quote you got seems a lil' bothersome to me, but I don't know what kind of tank, glass etc.
Do a search for "Diamond Hole Saw" on eBay, you'll find tons of bits for sale.
Personally, my buddy and I use a dremel with glass cutting bit and a template (wood or steel) and take my time etching through until I break through. It makes a ton of noise and a lot of dust, but does the job.
Dave
