rsi would say the value of the spanish mauser and bayonet value at 695.99 dollars
50-200 or so
100-500 USD or so
No. Two entirely different cartridges.
Your Spanish made Mauser rifle could be worth anywhere from $50-$300. Value of any gun is based on exact make, model, condition, and originality.
Yes.
Define 7mm. Do you mean 7mm Mauser ( a little less than 30-06), or 7mm Magnum, (a bit more than 30-06)
You will have to call Browning with the serial number.
No, they are not interchangeable.
The serial number indicates a Model 1893 Spanish Mauser manufactured in 1921. Yes, it would be a 7mm with gas exhaust hole on left.
Bayonet; 10-50 USD
$0 to over $1000. There's no way to be more specific without knowing what type of rifle it is. All we can determine is that it fires the 7mm Mauser cartridge. There are a lot of rifles - both military and civilian - which were designed to fire this cartridge.