I sell a lot of Euros. I use only Ti gold plating. For most blanks, or customer supplied wood, the are $35.00 each. With theme clips, I add $5.00.
Now, depending on who the customer is, I may, or may not, give what I call a 'friends and family' discount. That is $5.00 off per pen.
I don't do it out of charity. It has proven to be excellent advertising. The customer is asked to not reveal that they got a discount. I get a lot of referrals from this.
BTW, the reason(s) I charge the same for customer supplied wood are: 1) I don't want to be undercut and still want to make a good profit; 2) The wood usually is questionable (my experience), results may not be what you like to deliver from wood you choose; 3) and, if it is wood with historical significance, there is a considerable 'pucker' factor involved. If you screw up, there is no pen and the wood is lost and you have a customer bad mouthing you. You deserve to get paid for the stress.