Electrical is far less sensitive to moisture than data cables.
All you need is the cable which you can buy in 1000' or 500' rolls. Can see the link above for price reference. If you go with 500', you're looking at $100ish USD.
I assume you already have a good wire cutter so you don't need to buy another one of those.
You'll need an RJ45 crimper. I recommend one that ratchets to prevent over-squeezing on it. They run $20-40.
You'll need RJ45 crimp ends. They often come in bags of 100 for $10 or less. If you know someone that does a lot of installs (like your WISP), you might be able to bum some off of them.
You don't need boots but I recommend them. Bags of 50 can usually be had for less than $10. Again, might be able to bum these off of someone that does lots of installs.
You don't need a cable tester but I highly recommend getting one. They are the best way to test that you installed the ends correctly. I think this is the one I have which goes for $32:
https://www.amazon.com/Tripp-Lite-Continuity-Assemblies-N044-000-R/dp/B000VM6TTI/
So you're looking at around $200 USD total for all of the cable stuff. You could potentially be saving money down the road by not having to buy more cables too...just make them from the left over cable.
Here's the wire color guide you'd be using:
To be clear, the pair on the left is orange, the pair on the right is brown.
There's videos on YouTube of how to prep the cable for crimping and then crimping it. I look at the tip of the connector before crimping to verify I see copper in every hole. CAT5 is very easy to crimp compared to CAT6.