As minimal as possible, its sort of a first trailer for a small pony doing the odd show. Im looking for under £500 at least! Just a nice small, old rice trailer will do nothing special or expensive!
I bought a used single horse Cheval Liberte last year for £1900 - it was 10 months old at the time.
I really like it, as does my horse. I too however couldn't find a cheaper one. It's not narrow and unstable like the single horse trailers from years ago used to be!!
I have a single Ifor for my 16.2 mw mare. I bought it from new and was concerned about the horror stories of them being unstable etc. However, I've been assured that the new versions are very different from the older models and are completely stable. Three years on and I have to say I'm delighted with it. It's easy to tow and hitch up, and my mare loves it.
Despite popular myths, it's actually one and a half times the width of one side of the regular two horse trailers (if that makes sense) so I can even get my saddle on without having to unload (ideal when it's raining). It's the same width as the towing vehicle which means it's easier to tow. There aren't many secondhand ones around because a) they're not as popular and b) people who buy them hold on to them.
My mare isn't small but she's got loads of room to park her belly! Most people do comment about how there's much more room in it than they thought. Obviously, it's not for sale!
When I was trailer shopping I noticed there were alot of single ifors (401s) about, but nothing else!!! Cheval Liberte do a single horse one but you are looking at £2500 new, I haven't seen any of these second hand. Good lucK!