A buyer list is your own file of end buyers you can call when a property is under contract. Dispo is short for disposition, the sell side of a wholesale deal. You control a property at one price, you find someone who will take it at a higher one, and the difference is the spread. If you sell the contract itself rather than the house, the money you collect is called an assignment fee.
The software is where the list lives, not the list. A small CRM to hold buyer records commonly runs somewhere in the $50 to $150 a month range, and a sending tool for email or text is separate. Marketplace platforms let you post a deal to their buyer pool and usually take either a subscription or a slice of the fee. Prices move around, so confirm what a vendor charges in writing before you sign anything annual.
"Verified buyer" has no standard meaning. Loosely it means someone on the platform clicked a box. Strictly, what makes a buyer worth a row in your file is a buy box you can repeat back (price range, zip codes, condition they'll take), proof of funds or a lender letter, and a record of having actually closed something.
The part that catches people from your side of the business: blasting a property you don't own or control, to a list, can raise licensing questions depending on how your state writes its statute, and that applies to management licensees too. Ask a real estate attorney in your state before you send anything on someone else's deal. Thirty buyers who answer the phone beats four thousand email addresses.