I previously used searchanise on Magento which was awesome however it is not available on Neto. I have seen the Algolia option, however at about $499/mo plus installation it is out of our price range.
thank you!
This is a great question but unfortunately there's no simple answer. As you've discovered, most third party options are very expensive. They also aren't easy to implement. You're looking at a major development project.
I'm yet to tackle this on our site but when I do I intend on writing a detailed guide on how it was achieved.
I know Neto merchants who have attempted to use several providers but Algolia is by far the most popular and successful choice. I've never found a practical, cheaper alternative.
If site search is a big deal for you and you have the budget, it's worth discussing with a Neto partner.