I see,... When I was writing the comment I was thinking more in case you use a browser. I know Lubuntu uses about 200 Mo but once you start to use a browser with it, (for example, Chrome/Firefox can easily eat 0.8 Go RAM) you can quicklly be out of RAM. And the processor on a tablet/smartphone is weaker than a laptop
When I wanted to learn how to Linux I was buying a VPS with 1 Go RAM and used Openbox with it. It was using about 100 Mo but using a browser the RAM was filled pretty quickly. Arch is hard to use and Slax is for grandfathers
Sorry for the off-topic BTW.