01A shared-lead marketplace
A homeowner fills in a form. The contact record is sold to several firms at once, and each pays for it.
Where it hurts. You are racing three or more competitors to the same phone number. The homeowner gets three or four calls in ten minutes and picks whoever answered first, or none of you.
02A pay-per-call network
Calls are generated under a generic brand and divided among the several partners the vendor keeps in your area, with a fee per call the vendor deems valid.
Where it hurts. A call that rings four times, hits voicemail or reaches an answering service is still billed, answered or not. You never see what produced it, and when the price moves you find out on the invoice.
03Your own search ads
You bid on the keywords, build the landing page, answer the phone and absorb every click that goes nowhere.
Where it hurts. You carry the full media cost and the full cost of learning what works, while the firm down the road bids against you for the same twelve keywords.