Recommendations?

Spit is useless. Almost all lubes are way too expensive.

I have looked at the ingredients of good lubes to find out what lubes are made of, and found some very cheap alternatives.  Keep in mind that although these are not toxic, you should avoid swallowing too much because most of them have a laxative effect. You can use these alone or combine them:  glycerin (clear, thick, sticky, sweet tasting);  propylene glycol - miralax is one name they put on it (typically comes in a powder and you add water); coconut oil; aloe vera gel.  Probably the easiest to obtain is the coconut oil.

people say water-based is the best

I personally don't like water based. I don't take them into account because they dry out v. quickly. With my partner who has a huge penis I use Mr S Leather FIST, which I also use to prepare myself. I tested a lot and this is the best. Try it. It is very slippery, a little creamy, can be used with condoms, but cleans off skin very easily. Many other lubes were hard to clean, you are all kind of oily afterwards.
But the powder version is not good enough.

With my earlier parter, who was more 'managable' size, and we had sex bareback I did use spit. But I already had some lube "inside".