Maplin Electronics £15.99
RS Components £15.46
Maplin Electronics £1.39
Amazon £4.99
NB: before Brexit these were less than half price :Õ(
Bluechargedirect £0.99
For drums:
(1m should be enough for the circumference of a caixa, hep or timba - you may need more for surdos or more elaborate patterns)
Happychrisji (China) £20.86 per 5m
Chinly2012 (China) £17.24 per 5m
Makersify (UK) £16.00 per 1m(!)
Proto-PIC (UK) £14.82 per 1m(!)
Alternatively, for glasses:
czb6721960 (China) £4.31
Cool Components £15.98
CPC Farnell £15.98
I used a combination of CAT 5 cable I had kicking about and m/f DuPont wires to create detachable connectors.