Market research firms use a screening questionnaire to find participants with the right qualifications, and writing a good screener takes some experience. If you're new to this, you may want to reach out to someone who's done it before.
Also, Braintree founder Bryan Johnson used the same trick to sell payment services to local retailers. As soon as he entered a store, he offered $100 to shop owners for their time to hear the sales pitch. It lowered barriers and in the end each prospect was just looking for an end to their problems, with no more of the broken promises and over promises he got from other providers. He made sales, and learned why customers buy.
WP Engine now does over $100M in sales per year, and Bryan Johnson sold Braintree to PayPal for $800M.
The money offer helped a lot to recruit participants because with this treat it was more easy for colleagues to advertise the interview with friends and family.
Using friends and family as a lead is always most effective.