Please Help Me To Estimate The Value

Hello, what is the approximate market value of these two stamps? The 30-cent stamp also has a very interesting-looking square red postmark; could it be something special? I would be very grateful for any expert opinion.

EDit: without coffee in the morning I thought it was a Scott 38 - it's obviously a 71 - doh. GMC gave you a better estimate.

Market value is always a rough guess, but the stamp on the left, Scott#38 would probably sell in the $150-$200 range if there are no hidden faults. Hold it up to the light and make sure there are no thin spots on the paper. The other, Scott#70 with the hinge as it looks, probably will be around the $50 range. If the hinge can be removed without damaging the stamp it might get a little more.

I think maybe Risny is a being generous on the 30 cent Scott 71. It would likely sell for 50.00 US\ 45 Euros or so. Depending on the condition, thins, tears, etc. would all lessen the value. The Scott 70,the 24 cent issue, I doubt would bring 50.00 US in that condition. The cancel obliterates much of the face,the centering is average, and the condition is to be determined. I wish you the best of luck.
regards mark

Thanks for your both Expertise, and the Red cancel on the 30 ist Not something Special?

It really is a nice cancel, but the underlying value is the stamp itself. It's too bad the cancel on the 70 overwhelms the portrait as it appears to be a nice strike,perhaps a little underinked, but a nice impression.
cheers mark

IMO the boxed red marking is an Aachen Franco handstamp. It is just a partial and likely is not enough to add value since there is no cover for context.

As a seller or as a buyer? There is no one answer.

thanks for your expertise :)

as a seller

As a seller, if the market price is X, you will not get X for it even if someone pays X. The X will be reduced by the costs you incurred to sell your item. Likewise if a buyer is willing to agree the item is worth X, they will not pay X, they will offer X minus sale taxes, custom fees, shipping and handling such that their out of pocket final cost does not exceed X.

If you do mail order rather than ebay, I may pay more as I am not assessed sales tax (8.25%) for mail order from out of state and you may charge less since you will not have ebay or perhaps PayPal fees.