Please help: Keeping dev costs low

I started a business and am about to roll out the first version of my product. I am confident in the product and am excited about the current prospects who are genuinely interested. I don’t really have the finances to pour into further development as the initial dev cost a lot of money. What do you guys recommend based on past experiences.

I also am going through a development firm and it will cost nearly 45k for three months of development going forward. That’s maintenance and further builds. I wouldn’t complain but the first “sale” is going to have to be heavily discounted as it will be a pilot site.

Any input is greatly appreciated.