You can do that with small batches targeted with envelopes, letters, flyer etc. But you end up in the same place and its a PIA doing those envelopes every month.
Need good job averages for direct mail in my humble experience.
If your going to use direct mail look into "Every Door Direct Mail" from the post office. It's free to set up and the rates for mailing are great. Buy your postcards from Gotprint.com for awesome deals . If you need more help check out John Braun's program www.hitmanadvertising.com
If you got .02% the real question is what was your ROI?
If it was good you have the answer. Don't ask us yahoos.
Let the data you are tracking make your decision. If you do not have data from a past campaign you can not make solid business decisions to run your company.
I fire marketing sources every year because they do not bring me returns. We fired two last month. We give them the data and they can either lower the price or we part as friends. It's not personal it's business!
I must have
3to1 to break even,
4to1 to have some profit and
5to1 or better makes me not ask questions when it is time to re up my contracts.
In the words of mister wonderful from Shark Tank " I want to send my dollars out and I want them to bring back their friends"