Hey Rany,
Gremlin:
I'd say right now you're looking at about +150 to +180 (possibly a bit more if tier 2 or above)
Ghost:
Worth about +225 to +255 currently (the foot guard BPs have been dropping a lot over the last ~7 months so foot are going for ~100 ped these days)
Bear:
This one doesn't seem to be as common as it used to be. At least +1450 but maybe a bit more depending on tier levels and TIR #s.
Cheers,
Legends