Does anyone know anything about "Bella Girls"?
Here is their web site, with a link to a girl who had a post on CL or backpage (I can't remember) recently.
http://bella-girls.com/megan/
Her email back to mine said to sign up with the agency's web site to book an appt. and that it cost $1 (or something like that).
Seemed like a scam. Any thoughts?

... you KNOW that it's a scam.  Verification that you're over 18 (and all we want is your credit card info)? Paying to just be able to book an appointment?  C'mon... what escort business is going to set up an additional roadblock like paying to see their escorts if they really want to do business with you?

Steer clear... it's a scam for sure.

When you try to contact them by email (no phone number listed) they ask you for a CC number. No legitimate agency would do this.

Stay away, there are plenty of great indie and agency options to choose from in Boston.  There is no reason to go looking for trouble.