You can get cash instead of a credit voucher if you’re the last club member. Otherwise, all members need to purchase a vehicle to use the credit. This is done to preserve loan availability and protect members from defaulting on payments.
If, however, you have already received your credit voucher, you may sell it to another person and get paid in cash for that sale. The voucher will work no matter who uses it, but only once. If you'd like to sell or gift it to another person, it's totally within your rights to do so. Credit voucher sales can be quite profitable. Selling them is a common practice in countries where savings clubs already exist.