If you can find a 50m rope at a good price (Go Outdoor / Decathlon / local climbing shop sale), don't discount it as you can use the same rope on outdoor crags.
What rope length is required for the climbing walls you use? Many only require 30 metres. A relatively cheap 30m rope from your local climbing store, Go Outdoors or Decathlon could do the job.
Video Nils Favre develops new Chironico bouldering area
With the sun coming out and dry rock showing its face for the first time in what seems like a lifetime, here's a video to get you inspired to get out there and get back on that old project, or maybe find one that's yet to be climbed.