Ali's alternative is a good one but if that is out of budget too then your only real option is the wood glue/PVA method. It works but it is a time-consuming and you need a well-ventilated area for application and drying unless you want to get a thick head. Drying takes hours and hours but peeling the dried glue caste off is quite good fun.
Don't be tempted to wash them in the sink with fairy liquid or any of the other half-brained suggestions you might see around.
Current Lash Up:
TEAC VRDS 701T > Sony TAE1000ESD > Krell KSA50S > JM Labs Focal Electra 926.