My first deal came from the thousands of postcards that I mailed out to private note sellers in TX.

When you mail postcards, you short-target only those homes you like and you write something different depending on where it is so you can connect.

I'll tell you that is 100x better than any Google ad, FB ad, or postcard. 

Then you would mail each person on that list a postcard or letter saying “We Buy Houses” etc.

You are better off making a small investment on your own, maybe a two-family, and use it as a proof of concept.If you don't know anything, trying to source deals off-market will just be taking money and burning it on postcards without the correct systems behind and the incentive for people to call.

Property Radar just released a new dirt mail system for the program offering postcards at .48 per and it's already linked to all my lead lists and properties I have found.

If you want to do postcards, DealMachine has a way that you can send post cards directly from the app/site.

Mailing is easy, and you are leaving people with a postcard or letter they can keep (I have had people call me 9 months after they received a postcard), but it can get expensive.

How often should I be sending out letters/postcards to these people?

I've done post cards etc.