I have a box that sits in the closet and runs a bridge/relay. Bandwidth on a commercial grade cable connection is minimal, and I don't notice it at all. I've successfully run Tor nodes on boxes with 300 Mhz processors and only 128MB of memory, so yeah, I'm guessing a tiny VPS wouldn't have trouble with it.
I don't run an exit, and won't be running an exit, but it is simple enough to run a bridge/relay that I'm surprised how few people do.
A really helpful piece of software is arm: https://blog.torproject.org/blog/arm-release-140 really useful way of monitoring how much bandwidth tor is using. It also allows you to edit/reset you torrc with a couple of keys. It keeps stats on how much data your passing through the network too, which is pretty cool.
I've had no problems from my ISP (Comcast), but then again I do pay for their commercial grade service, which doesn't have ToS restrictions on proxies. (I used to run a node out of my residential Comcast connection too-- they didn't seem to mind).