I try to be as fair as possible by basing my prices from recent eBay completed listings. Looking over them now...
It seems as if Unown G are going for about $5.00 each. There's some going for $4.xx, and a few going a bit over $5.00, and then there's a lot of 2 RH going for $13.00 and then a lot of 4 that went for $17.00
Dialga G Lv. X seems to be going for $10.00 - $20.00. More recent auctions go for $12.00 - $15.00, but there are some that hit $20.00 and higher.
The only listing for Call Energy I found was a lot of 4 for $11.50, so roughly $3.00 each.
Feel free to make an offer, and thanks for the interest.