Ok, I'll try to make myself more clear: damage to a tablet's touchscreen can be a complex affair, and is in no way comparable to fixing a broken mirror on a car (sorry). If it's just the glass that is affected, it shouldn't cost a lot to replace it (I have done so on a Nexus One a few years ago), but if you need to replace the digitizer, it'll cost you more. That's why most repair shops will provide an estimate but won't be upfront about the exact cost before having the chance to examine the unit firsthand.
And again, I feel your pain, but you should know this is standard procedure in most cases.
EDIT: ssl123 clarified the point even better than I did. Thanks.
"Why Genghis Khan was good for the planet: laying waste to land scrubbed 700m tonnes of carbon dioxide from the atmosphere." The Guardian, Jan. 26th 2011