I purchased my black left hand M&P full size(#25) SERPA holster for approx $28.00 from a smaller online retail site called; www.natchezss.com
They have several models in the Blackhawk line. I don't recall if they had the SERPA for the P30 pistols in stock. Natchez also has Eagle holsters around $18-$19.00 in different colors(black, OD, tan).
If Natchez doesn't have a HK P30 holster you may need to buy the SERPA directly from Blackhawk.com.
The sale price may be higher.