I have bought some credit on Aruba. . .

Looked at Aruba offerings, check this out

https://serverdedicati.aruba.it/server-dedicati/basic-1-3.aspx

For 15 euros/month you can have a dedicated dual-core 1.6GHz with 100MBPS unmetered traffic. This will make a rather nice exit node for the cost and will run better than a typical VPS where one has no control over system load. Even with the low clock-speed, network processing latency will be very good.

Probably is an Atom or maybe a Celeron CPU and the it will probably run at close to 100%--not a problem. If one 'tor' instance does not use more than 30-40% of the 100MBPS due to limited CPU, fire up a second relay. Up to two relays can run on a single IP address.

But if one 'tor' instance runs at 50-60% of bandwidth or better it would make sense to stick with just the one.

Non-exit relays typically load at 25-35%; is the intentional design of the bandwidth allocation system. However due to the relative shortage of them, exits run more like 80% of useable bandwidth as determined by the BWauths.