50 gold may be a decent sum for a lowly knight, but for a duke or other person with high income, that's pocket change. If I was an adventurer looking to sell an item, I'd probably be offering it to the rich people in the realm, and trust me, unless the realm is doing poorly in a realm, they're not going to care much about a mere 50 gold.
50 gold is more than 2 of my lord characters are making,
combined. One of those is a newly TO'd region, to be sure, but the other is a rural with a single knight and control issues (large realm penalties are limiting my tax rate to 7%) (FEI)
Of course, my other lord made almost 400 gold (DWI), and my knight makes 116 gold (AT).