Any legitimate pay at closing referral services?

As a new agent I’m trying to utilize all I can to get some business going. My brokerage provides leads, but my understanding is you sort of have to earn them. Show initiative. Etc.
so, I’ve been looking into referral sites. Most seem like a scam. I have a background in sales and business so I’m not against paying for leads. Ideally I’m looking for a pay at close model. Most have wanted a large retainer or a monthly fee.
I suppose a reasonable monthly fee is ok but then they also want a hefty percentage of the commission.
Does anyone have experience with these and can recommend a good platform?