It probably depends on how committed you are to keeping them long term, to make it worthwhile, but we've recently moved and had to leave behind my shonky old run which I built from fence posts, wire and tin roofing sheets.
I thought I would not be able to have the girls in anything as useful (it was about 5 metres by 2.5 and always dry/dusty inside) but though our garden is smaller, I've found a pretty good solution.
It's one of these - there are a lot of different ones on ebay, from various sellers but you have to make sure you get the sort with a square edged door as otherwise it's easy prey for rodents (and we had a big rat problem before we moved).
It took me about a day or so to put up, well, if you condense it probably about 2 hours but I faffed about a lot! The hardest bit it putting on the wire netting but it is cut to size, so you just cable tie it onto the frame.
It isn't perfect, but it is very easy to use and the girls (plus rabbits) seem very happy in there. To make it dry I got a Monotex clear/white tarpaulin, from here which was £21 and covered the whole thing with some overhang at one side (had to get the 4x3 as the roof pitch means you need about 3.5m width).
I should say there are a few minor issues with the run - a couple of bolts weren't great but it doesn't affect it as the structure + wire holds it all together perfectly anyway...the green tarp supplied with it didn't stretch far enough and made it dark, and was weak, so we kept it for use elsewhere.
Also, when you are inside, you can pull the door closed but then have to poke your fingers through the wire to let yourself out - not perfect, but doable! I also use a cable lock to make sure it's secure at night as you can't use a padlock on this catch (bit of an oversight...)
The monotex tarp lets a lot of light through which is lovely. tbh I'm not sure how I coped before.
I just thought I'd share as I was always looking for a decent run within budget - we actually have their Forsham coop in there, and two six foot rabbit hutches on top of each other and that's the 3m x 3m version.
Anyway I hope this helps by way of a sort of review - I promise I don't work for either company!