Hi,
You'll need the licence for towing, but this is quite an easy test really - I know, as I did in the summer. Just got to reverse a slalom of cones, couple and uncouple the trailer, and be able to ask a couple of common sense answers. It would seem that reversing a trailer is one of the only two things I'm actually talented at in real life - that, and finding things people have dropped on the floor, like nuts or washers.
Maintainence is, in the most part, restricted to oil changes, battery charging and brake bleeding, but there will come a time when a rod-end, wheelbearing or brake disc wears out - these are the buggers that cost the money, and are a bit harder to do, but it's not beyond the wit of most home-mechanics to do them with a reasonable toolbox. Some cars seem to get through rod-ends and wheelbearings like there is no tomorrow, others go for ages without them even needing to be looked at, but you'll only find out which they are once you've got one.
Other costs, that you can't predict, are damage repairs. Usually some bodywork and maybe a corner of wishbones if you're only slightly unlucky. Some of the Mono cars go back to the 70s and are still able to be kept running in near original specification without having to own your own bank (which isn't a good thing at the moment anyway), but again it varies drastically between cars. Some of the 1600/1800 cars are very cheap to maintain, whereas some of the really quick stuff in Mono2000 or Mono1000 might be a bit more.
Car hire is available, I believe, if you know who to ask. I don't (but I'd like to know one day, just in case I get an urge to try out something bike engined).
I was new to racing a couple of years ago, and new to Monoposto at the same time. The learning curve has been steep (and it remains so, perhaps steeper than ever), but the Mono crowd have been incredibly helpful with advice, time and pointers. You won't go far wrong as a member of the club - it's not an out of date 'slogan' when Mono proclaims itself "The Friendly Club".
Presumably, by your posting in the Mono1000&1400 section (what I lovingly call the MiniMonos, but this doesn't sit well with some of the competitiors in it

), you are interested in the bike engined end of the market. And from what I can gather from chats in the paddock about their cars the Jedis and Speads are hardy little things that are very easy to maintain, but perhaps with not the cheapest spares if you're trying to keep it 'original'. But there are always cheaper non-original alternatives out there if you prefer it!
And don't worry about being a relative novice on the track - in the last couple of years there have been half a dozen or more total novices taking to Mono with some success - they are the ones with the huge grins in the paddock, even when it's raining and their working in the mud - I've found the grins wear off after a while though
Any you'll find, within a day or two, many replies from vastly more experienced people than myself that will be even more useful than what I can offer. But I think the ultimate message won't be wildly different.
Mr Dermot Healy (see the Board Index for his number, and take the time to read his very funny adverts) comes wildly recommended by all, and seems to know of cars, parts or hire-and-drives that just so happen to be what you are after. And if you're not interested in spending money when you call him, you'll have done so anyway by the time you put the phone down. Even if you don't own a racing car!!!!!
Good luck, and we all hope to see you on the grid this year or next.