Look to your shipping.
There is a difference in philosophy.
One will charge $9.49 for a part.
One will charge $7.95 for a part.
However, shipping costs vary. One makes the price a bit higher, but the shipping cost is flat rate, and lower.
The $9.49 has shipping to me of $8.99, making my cost $18.48
The $7.95 has shipping to me of $11.62 making my cost $19.57
What is the philosophy here? One subsidizes shipping with higher pricing. The other offers a lower sticker price, but charges you EXACTLY what the shipper charges them. They aren't upcharging the shipping cost, that's what it is.
All of this is moot.
While I like to get things cheap, and... (puts on his granny glasses, walks with a stoop, talks with a high wavering voice...)
'Back in my day we'd buy drop targets five fer a doller. 'An we liked it!'
Hehe.
New Stern Premium pinballs in my area with sales tax are now over $10,000.00.
Relative to the cost of the machines today, ANYTHING you pay in parts is insignificant.
We can shout as much as we want about how someone is (gasp) charging money... for something that I think shouldn't cost me as much!!!
But at the end of the day, I'm personally just happy to HAVE a plasma display for a 90's pinball. $499 hurts my feelings, but I'll pay, and I'll be glad to get it.
Not having parts sucks ever so much more than paying for parts.
As to why a part might cost more... Quality matters, sourcing matters, WHEN you purchased the part in bulk matters, whether you bought in massive bulk, or just a few hundred at a time matters. All of that isn't available to us, the buying public to evaluate.