You can´t find sandshrew in Fire Red, you have to trade from another versions, like leaf green.
However, in Leaf Green you can find it West of Lt. Surge's town.
You can not catch Sandshrew in Pokemon Firered. It is Leafgreen exclusive. Firered gets Ekans instead.
The only way to obtain sandshrew is to trade it from Leafgreen, Ruby, Sapphire or Emerald. It does not appear in FireRed, I think.
You find it in the grass patch left of the city that mistys gym is in
i caught mine on the path from Cerulean city to Rock Tunnel
after beating the game, insert the Pokemon leafgreen version for gameboy advanced in the GBA slot. You can then catch Pokemon from that version.
You can't find a Vulpix in Pokemon FireRed version. That pokemon is version-exclusive to Pokemon LeafGreen.
While it was possible to find missingno. in Red version, it is not possible to find it in FireRed.
You Can Not Catch Celabi In Pokemon Firered Unless you trade with pokemon heartgold or soulsilver.
You cannot find Sandshrew in Pokemon Red. Sandshrew appears as an exclusive Pokemon in Pokemon Blue but can be traded to Pokemon Red. In Pokemon Blue Sandshrew appears on Routes 4, 8, 9, 10, 11, and 23.
You must trade it from Pokemon firered or Pokemon leafgreen
viridian city
You can find the gameshark codes for Pokemon Fire Red the European version by following the website: