Hi,
I use a seat from autostyle.nl - you can get them in germany (from ebay incl. Shipping) for 150 €. For this price they are ok but i have to say that they become a bit uncomfortable after longer sessions. The recaro spg or pole position is really nice but around 4times as expensive ;-(
Depending on where you come from a Kirkey (economy) could be a great alternative and has some diy options for the future (google @ gs-4

)