>I contacted a couple of services that help with this kind of migration, but their quotes were way over my budget
I guess I'm "that guy." Have you considered that the reason is this as you say is niche thing and there simply is not the market to make it profitable? That is the reason they have to charge out of your budget for it to be worth their time?
Maybe the maintenance and upkeep of the site is low enough that it doesn't matter. (I do hope so i'm not here to watch people fail.)
I would actually target it at those exact businesses rather than individuals. B2B tool. Let them handle the mess of sales negotiations and change your pricing model to the number of accounts or something like that. Accounting firms always have a million high priced tiny tools they use for odd cases. Ask me how I know.....
You might be and I hope there are no hard feelings about me launching such a tool but as I mentioned this is something I wished existed when I had to go through this process and while I understand charging more because it's a niche market, my set up was quite "simple" and I think it can help solo indie entrepreneurs in the same situation. This is not my main business and the lower price should attract customers now and help us understand different set ups which might need a custom solution and a custom price. On your last paragraph are you suggesting a partnership? If so you can contact us through the website.
My bad, I read “let them handle” as “let me handle”. Thanks for the advice.