The first bummer when I've started to explore cryptocurrency algotrading back in 2017 was a complete absence of good enough historical data.
What I could find was either of low quality, requiring semi-manual cleansing; extremely expensive; very low resolution - hourly at best or a trickle through a rate-limited API.
Once I've built an automated mechanism to keep the data up-to-date I've realised that it may save heaps of time for fellow algotrading enthusiasts.
So I've put together this simple website, with all 1-minute bar historical data available for free and higher resolution tick data for a moderate access fee.
The data is refreshed continuosly through the day and generally shouldn't be older than several hours.