i have around 2.3k hours in gmod and i'm gonna tell you right now: you dont need to buy stuff to replace the missing textures.
just go download some cs:s textures, people go richarding around saying its essentially piracy but it isn't, why?
because you can get the textures from steamcmd and downloading the cs:s dedicated server which is free to download, garry has even stated this before i believe. he just can't package the textures with the game because of legality reasons, like how you can't package a free to play games textures into another free to play game. valve has different rules about this then most companies allowing gmod to at least go this far, if valve was like any other company gmod wouldnt even exist.
hl2 ep2 is the one exception to the rule and gmod does NOT include ep2 textures. so if you're gonna buy anything for textures buy that.
if you don't like loving about with textures every time you fresh install gmod, go ahead and buy that too.
