they did cut down bayonets at the beginning of ww2 to use on the garand so it's a possibility
does the groove go all the way to the end? if it does then it was a cut down 1903 bayonet
$80-$100 with scabbard and whether it has the official sharpening and condition is always important to value. The value of bayonets have really dropped since 2012. This is only my opinion.
10 years ago, I sold a standard original WWII Garand bayonet in good condition, with scabbard, for $75.
I haven't followed the values since then, but that's where I'd start for a ballpark.
P.S. Don't forget that during the 1930s, surplus 1903 Springfield bayonets were plentiful and dirt cheap. Is it possible that some private citizen bought one for $2 and ground it down himself to make a more practical fighting knife out of it?
Maybe this was a bayonet ground down in the 1960s by a private citizen who just obtained an M1 Garand and wanted an appropriate-length bayonet for it, and happened to have an old 1903 pig-sticker handy...
Billy Bob is more likely to sharpen or polish a bayonet than cut one down, $2 or not.
I've watched (and cringed) when momos take a perfectly mint 1903 pattern bayonet to the knife man and the gunshow and have him sharpen it for them.
Yours looks like a cut-down and with scabbard, as others have pointed out, is worth about $80 to $125 depending. It looks reworked for WWII, black scales, etc.
Look at the bright side. When I started collecting, these had little desirability. Now they have a niche collector market.