For POO to play out of town, you're basically going to attract a hand-full of people to the gig, and therefore really can only command a small form payment to go towards travel expenses. As for bands from Aberdeen, who play in Aberdeen, sure you would expect payment for your time but obviously you have no direct expenses so surely even 20 makes the gig worthwhile? Afterall, at the stage that the majority of bands in Aberdeen are at, you're giving up your time in order to gain experience, build a fanbase and get exposure. Expenses like practise time, string etc are in no way related to the gig. You've decided to play in a band, and therefore you've accepted that you're going to have to pay these costs.