Depending on CONDITION and of course rarity, they range from $50 to $200.
If they are without scabbards, not pitted or chipped, $50+
If they have scabbards that are torn, missing parts, chipped/rusty/pitted blades, broken grip panels etc., $50+.
If the scabbards are complete, not torn and sewing intact with clean unsharpened blades and all grip panels intact, $120+.
Bayonet by itself, no scabbard in VG condition $75+.
These are ball park figures. Many here still remember the days of walking into hardware stores and buying them out of boxes or 5 gallon metal pails for $1 each, in as new condition and 50 cents each for the lesser grades.
I bought 3 cases of 100 bayos/case for $10/case or $20/3 cases in 1965. This was dealers price of course but if I had bought 10 cases, it would have cost $50 plus tax. All I can say is we are all blessed with hindsight.
OP, smellie is right. If that Pattern 13 bayo is complete with scabbard and in VG condition, $50 would be stealing it.
The Pattern 13 rifle was the predecessor to the Pattern 14 and was chambered in the rimless .276 Enfield round. Not many of the rifles were built. That being said, the Pattern 17 was mass procuced for the US government when Springfield Armories couldn't keep up with production, when the US joined in the WWI effort. The only real differences between the P13 and the P17 are the finger grooves on the fore end and of course the chambering which is 30-06 in the P17.
The p13 bayo, fits the p13/p13/p17. They aren't rare by any means but they are not usually in VG to EXC condition.