There are USB powered dew heaters on amazon for pretty cheap, and work just fine for small lenses. I think I got mine for $15 a few years ago, and I already had a battery pack laying around. In a pinch you could use some non-reusable iron oxide hand warmers rubber banded to the lens, which could give a couple hours of warmth.
In terms of trackers the cheapest I've seen is the Nyx tracker at $130, but I know some people have managed to DIY them for a little cheaper. I've never used one so I cant speak for how well it works, but I imagine you'll at least be able to get some longer exposure times if it's polar aligned well.