Hi there 
Some weeks ago I was looking for an easy way to collect and store logs for my apps. I wanted a custom UI to easy see the app/instance the log came from, simple filter/search, and less-expensive long-term storage on fly.io.
I didn’t find any so I created one for myself. If you’re interested in using it, you can get it with the source code and set up instruction here. I’m offering a 50% discount for the first 30 purchase (it’s a lifetime license) using the discount code FLY_50_1. The video on that page shows how it works and likely cost savings if you’re looking to save cost to keep your logs for longer than 3-days compared to most SaaS options.