You've probably already read Erin's post on clearing Chakras:
Chakras
Her post yesterday has useful information, too:
How do you open and close chakras?
$300 sounds excessive to me. I've visited skilled practitioners of many types who charge in the $100 to $150 range for 1-1.5 hours, and more than one of those does energy work and clears chakras. (Here's an example of someone with standard/reasonable prices:
Bente Hansen)
The "you have a blockage that I will fix for $300" vibe is a HUGE turn-off for me, too. It feels manipulative.