Losant is good but in my instance I cannot get what I need at a reasonable price. I have therefore used Thingsboard.io CE version (open source and free) on an Ubuntu 18.04 server on a simple low cost dedicated PC and have had great success. YMMV
Losant’s free service has allowed me to do everything I have ever wanted for more than a year now. See if they still provide sandbox accounts and you should be good to go, I haven’t found anything else that is near as nice for no charge.
@worldburger Grafana’s interface is pretty if you are looking for a free alternative. I know SORACOM has a “free” hosted version. (you need to use their data pipeline though )
I actually self-host my instance using InfluxDB as the backend. It’s been running since early April in one capacity or another. If you’re not afraid of a little bit of Docker dev ops you can get it up and running quick. Plus it integrates nicely with Particle Webhooks.