I changed my battery myself. Below is a breakdown of the costs.
New battery from wal mart- $75
wrench- $2
shirt which was ruined by acid while carrying old battery- $15
backpack ruined by acid while old battery was sitting in trunk- $50
total- $142
I also sold the old one for $20 since it still had some life.
net total- $122
price to have battery changed by mechanic- $100??
Net savings- negative $22