Small tent, something like a Blacks Octane 1, enough room to sleep with your biking kit in the sleep area - £50-300
Roll up self inflating matress, still the biggest thing you'll need to carry but a good night's sleep is invaluable - £5-20
Good sleeping bag, depending on when you're planning on camping 2/3 season, remember you can line it to make it warmer but if it's too hot you'll be uncomfortable - £20-100
Only thing I haven't worked out yet is the pillow, inflatables are uncomfy and the towel wrapped in a jumper is not quite right, still working on that one
Hard panniers are, officially, the nuts when it comes to going away, but soft panniers will work just fine, I usually managed to do a weekend away with a tankbag and rucksack so could strap tent etc to the pillion seat
This is mine loaded for a recent weekend away, frankly the panniers are obscenely OTT, I took a stove I never used and a load of clothes I never wore, but it looks daft with just one pannier and I haven't got a topbox...
