Price depends on plugins,i wouldnt mind a srb.
What i will pay max is 500€ with a LOT of plugins like flexor/synths n sampler/mix n master,maybe a few zarg synths.
For a "standart" card plugwise i gladly pay 400 to 450.
For a srb with "not so many" plugs 350 to 400.
It all depends.

Only want a 14/15 dsp card as i max out my 14 dsp rig(pulsar 2 and pulsar1 x2) quick.