I once had a someone ask, "How much would it be for 100 of these?" She was referring to my engraved log candle holders. I cut each one, drill each one, sand each one, dremel each one and top coat each one - it is more work than it looks.
Anyway, I told her how much they were and she wanted me to go 50% off because of the amount. I am at the stage where if I am going to put that much work into something, I would like to get paid for my hard work. Not just barely break even.
I was also asked how much a $25 item would be is she bought 45 of them. I called a friend who said, 'Tell her it is $25 X 45....end of story."
In reality, I will give a bit (maybe a dollar or two per item) and I will group them so the shipping is much cheaper, but other than that, my time is worth a lot to me and so should yours. I don't understand why people who spend all their time working very hard to make something should have to barely break even by giving a discount just because more of the same items were ordered. If 50 customers bought one each, it would be a lot of time to make and no discount would be offered. If one customer ordered 50, same amount of time and effort, we feel we must give a big discount - I don't get that at all.
Don't sell yourself short. You are worth more than that. :)