Omg! Crazy prices!
I recomend desertboys advice and ask forum members for help.
For reference I got all my plates milled, pocketed, tapped and ground for about £200. Material included. 15 and 20mm thick steel.
The guy was super nice so I basically paid for material cost in weight and a tap that broke during the job.
I was lucky to find a member on a forum locally in sweden :)

Skickat från min SM-G955F via Tapatalk