I'd like to get a PAYG SIM for a spare phone for a family member and pay cash for the connection (so there's no possibility of bill shock). There's a fair chance the phone is going to get lost at some point, so I'd rather minimise the amount of money tied up on the SIM and lost along with the phone.
I'm fairly sure I can top up a Three SIM with cash in £10 increments, but not smaller. That's what they told me in the shop the last time I bought a voucher anyway. Does anyone allow smaller cash top ups?
Worth browsing the above thread.