Donating residual balance "less than $5" from rebate cards ?

[foothillman]

I end up with a few cards that have a low balance every year.
These are always rebate or prepaid gift cards usually debit type.
Is it worth donating the residual balance to CRPA?
Are you charged a fee for the transaction that could result in a net loss?
Have cards with $5.00 to $0.30

Next question,

I have a 2A Sustaining Membership that makes low $ monthly donations and was wondering if a single yearly donation would make more sense.
If the card company charges lets say a $1.00 per transaction than more money would go to you if I just donate higher $ once a year.

I have no clue how much the service cost CRPA and prefer to make every penny count.

Thanks for all your work