50/36-34/28-30 is an unusual combination; I would not expect to find more than one or two of those on a complete crankset.
Gotta be patient and keep looking on eBay. Pounce when you find the right tooth count and BCD.
Over the last two months I’ve sold off maybe 20 hardly used chainrings, including a 50 big and a couple of 36 tooth middles & 28 inners, mostly for $12-18 including shipping.