I am going to put this here, but it is currently a closed program. When it opens back up, I will change this post. The LISN program is called Low Income Spay Neuter program. It is for people with lower incomes so that they can get their cats neutered. You can purchase a voucher for a lower cost surgery and make an appointment with any veterinary service that will accept the voucher. I know that Dehart Mobile Clinic accepts them and can usually get you in within a month.
** NOTE: In this program, you will not have ear tipping unless you request it. You are allowed to purchase 2 vouchers at a time and they do have an expiration date, so schedule your surgery asap.