After purchasing my first property last year, I have resumed cold calling after purchasing a second property this year.

Perhaps combine a direct mail campaign with your text message and cold call campaign.

Try driving for dollars, networking with brokers, and direct mail or cold calling for off-market leads.

After I got good at pulling leads that work, I can switch that ratio and spend $3 on leads and $7 on sending something to those leads;  post cards, sms, rvm, cold calling.   

There are trade off marketing channels such as cold calling and mass SMS. 

I’m relatively new to wholesaling, and I’ve been diving into the process—cold calling, direct mail, and driving for dollars.

The fact that they contacted you cold even though, I assume, you have ZERO interest in selling your rental pretty well sums up most of the marketing done by wannabe wholesalers.

I'm getting good results for our clients with postcards and some paid ads, but I'm looking at implementing cold email and cold calling as well.Any good companies to buy lists from?

It is normal to get cold feet but the main thing is to do the best due diligence you can do prior to going under contract-  "Pre-DD". 

Also from what I've read online breaking into the insurance side of things sounds like it requires cold calling and building relationships with those reps vs just registering property in database and waiting.