WP Air Fork Pump Equivalency

Hey all,

Just picked up a 23 GasGas MC350F, used. Prior owner didn't have the WP pump since he swapped out suspension on his son's race bike.

Any good less expensive alternatives or just order a new WP pump from dealer/website?

I've got a little bit of a learning curve with these air fork components since having been out of riding for 8+ years.

Thanks!