You only need the tm30 if you're doing anything at the immigration office. And if you are, just check into a cheap hotel, print out your reservation and get the hotel's business card to go get your TM30 paper from immigration.
that's the address report your landlord is supposed to do the day you move in.
If they didn't, you need to go do it at immigration, and you'll need your rental contract, the property's owners book and the same copies as a 90 day report.
You don't need to pay an agency 50,000+ baht. It's a simple application, just check your local embassy's website for the requirements and apply online.