I heard today at a conference that running an exit node can be upwards of $1000/day USD in bandwidth costs.
The same person says that it could cost over $100/day to run a middle node. I know this isn't true from personal experience.
This question is for people who actually run exit nodes, what kind of bandwidth are you actually using and do you find the financial costs to be prohibitive?
I would definitely recommend asking the person making the claim for the calculations underlying it. I suppose, if you had an all-open exit policy, and were in a location where traffic was fully-metered and very expensive, you might be able to rack up US$1,000/day in costs, but that is very far from the common case. Even if you were running an exit in such a location, you can limit usage using accounting, which this person appears to be unaware of.
The nodes I run are on unmetered (but contended) Gbit connections, and they cost less than US$100/month for machine and bandwidth.
Since you've got experience with the other claim that this person made -- that a middle node costs over $100/day to run -- and you know it to be false, I think you've got all the data you need to conclude that whoever made the statement about exit nodes is speaking from their posterior, and can be ignored.
The mentioned costs are definitely too much. It would be interesting to know what the base of this estimate is.
I run different kind of Tor nodes. The cheapest one is a BananaPi. This is attached to a 100 MBit connection and makes ~30 Mbit. This costs next to nothing.
You can also rent servers (sometimes a VPS works). So you can have a Tor node (middle or exit) with less than 50 € per month. If you ask for a guaranteed (as in dedicated) bandwidth (1 GBit or more), the costs will raise to several hundred per month.
When you want to run an exit relay, it is recommended to ask the provider first. It might be that the charge a bit more. Furthermore you will have some cost in the sense that you need to answer abuse mails. But also this amounts to less than an hour per week.
So in general I'd say that the mentioned cost are grossly overrated.
