I'd like some advice/opinions please

So, I had my hair cut pretty short before Christmas, and now it's a bit longer, and I'd like to keep it this way. Unfortunately it looks a little bit untidy, and mullety at the back.

Can I ask the lady for a little haircut, and can I expect to pay less. I don't want to pay 7 Euro for a few minutes work. Is this OK, or am I being a cheap bastard?

Thanks!