UPS shipping is based on dimensional weight, so prices can jump in a hurry on larger items. I have folks paying over $50 to get big ramps from the east coast to the west coast. Every inch counts, and I wind up having to stock a dozen box sizes just to save my customers some money. Not much else I can do there, even with discounts applied. $13 seems to be about normal to me recently. USPS really got bad with any package over their small sized sweet spot. They are sending the message that they just don't want to deal with packages over a cubic foot. I usually default to USPS when I order small items, because they are typically faster. But now that they jacked up prices on medium sized parcels, I'm picking UPS more often.

I avoid FedEx at all costs.

You could just drive to them and pick it up if you want to be cheap.

Pricing depends on volume. Not all pinball websites move enough volume to get crazy good discounts from shippers. Yes, Shipstation and Shopify get you discounts, but it's still higher than what the big guns get. Boxes are not cheap either. $4-$7 each for a large ramp box plus packing materials all add up. You have to buy boxes in bundles and bubble wrap/craft paper in bulk to get any kind of reasonable price on them. I'm out several hundred dollars just getting to the point of being able to ship something. Sorry, none of us are billion dollar companies like Amazon, so you may be a bit let down that you won't be receiving your pinball parts in a day with free shipping for a nominal $13/month.