I plan on doing a mailing with postcards.

Keep in mind that direct mail tends to work best when you send a campaign of 5-7 different pieces (postcards, yellow letters, typed letters, zip letters, etc.), 4 weeks apart from each other.

Hello George.We all as investors face the same opportunities, finding a good deal and getting it under contract for what the property is worth (taking into account financials, terms, rehab, etc.) and getting it closed, so we can turn a profit.I can only assume you are just getting started in investing based on your question (I could be wrong), so my first action item for you would be to market to these owners through post cards, letters, door knocking, email, phone, social media, etc. so you can gauge interest in selling. 

I think you might be able to find local printers that can do simple mailers/postcards, however, if you're really looking to get creative with your mailers so you stand out, I can almost guarantee there are only a number of print shops that can do this due to the additional cost of the mailers.  

It helps me to network and provide value to other investors I network with.With all of those perks being discussed, let's take a look at the math on the marketing side:Let's use 2 hypothetical lists for example:1) My scrubbed list of probates to check the probate records for "real property being inherited" and a different mailing address for the applicant and the inherited or soon to be inherited property.2) A random list pulled from ListSource containing certain criteria of out of state absentee and 90% or more equity in the house.List 1:mailing 1000x5 times with a postcard costing $.50 ($2,500) (hypothetically let's say 80% of these leads have motivation) ($500 is in vain)List 2:same $2500, except only 50% of these leads have motivation of some sort, so there's more tire kickers and less potential. ($1250 will be in vain)With this math, the value of a great list will be worth at the very least $750 plus value in the market place, more concentrated motivation, and much less tire kickers.What does the BP community think?

I see spikes on website visit metrics every time we mail letters or postcards. 

I know that I get wholesalers send me a ton of letters, post cards, etc and usually I just call them toss them in the trash or call to network with them.

Did I spend effort doing KPI's, yellow postcard, blue post card, picture on postcard, no picture on postcard, postcard text1 vs postcard text 2, etc.etc?

I get it...But then you need to come up with some seriously amazing marketing idea.. be it mailer piece, or.. well anything different from the norm that will draw attention.But if you are just going to follow the herd, sent a yellow postcard with I want to $BUY$ your house...seriously.. you are winging it.

To save you time though I would find a company that will create a postcard for you and send cards to the entire list.