[oldelpaso]

Check out Argos or any kitchenware store, they'll have a decent set of cheap digital scales in there so there's no need to fork out for anything too fancy 8)

 

[oldelpaso]

Fishing scales aren't too good as you have to keep really still and steady to use them...

What snakes are you weighing? Most kitchen scales go up to 2-3kg which is enough for a lot of the small to mid-sized snake species, whilst the postal ones maki is on about sound great for larger species 8)