ignition coil repair costs

Hey there, I was told by my mechanic that I need to replace 2 ignition coils, plugs & wires for my 92 cavalier. Cost = $505 + tax. Sounds a bit excessive to me, but I'm kinda clueless with things like this. Anyone have any idea if this sounds excessively expensive?

Thanks in advance

You can get the coils for $19.99 each, the wires for $24.99 & plugs for about $6.00 at autozone. The coils can be tough to change, I've changed mine twice.