it returns a number for example if i fire b as plrsell it returns 735 as plrsell when i print it on the server. it also does this with other characters be is just an example.
Problem 1: When you fire the RemoteEvent, Roblox automatically adds an argument that tells the server who fired it. For example, if you fire a RemoteEvent with ("hi"), the server will get (PlayerWhoFired, "hi").
Problem 2: When the MouseButton1Down event fires, it returns the X and Y coordinates of the mouse, not the player who clicked. The 735 is the X coordinate of your mouse.
Solution: Since solution 1 already told the server who fired the RemoteEvent, the plr variable isn’t needed.
Local Script:
script.Parent.sell.MouseButton1Down:Connect(function()
local plrsell = script.Parent.input.Text
game.ReplicatedStorage.clearauction:FireServer(plrsell)
print(plrsell)
end)