Cheapest way to get GMod and source games on Steam?

I’d love to try Garrys Mod and fancy making a few videos I haven’t seen on YouTube, and I was wandering what would be the cheapest way to get these games;

-Garry’s Mod
-HL2, episode 1 and 2

I currently have a few games including both Portals and TF2.

Should I get the Gmod and CS:S package, and the orange box from Steam? Or should I get the CS:S package and the Orange box retail version (Would I still get achievements as if I bought/DL from Steam, and would I need the disc in whilst playing?), or should I do something else like wait for a sale?

The CS:S and Gmod package is £15 and the Orange Box from Steam is £15, and I think £30 for a game with no point is maybe too much seeing as though I may not have enough patience for it.

I probably wouldn’t play CS:S, just use it for Gmod, but I probably would play the HL games.

TL;DR Should I pay £30 for CS:S, HL2+eps and GMod, is there a cheaper way to get all of them, or should I wait for a sale?

Thank You!

Well if you really want to wait during Christmas they will have a huge sale on the valve complete pack.

That could be interesting, thank you! :]

Christmas sale or summer sale. Either way, Valve is pretty generous with putting their own games on sale.

Yup yup, as said by everybody. Games can get as low as $5 depending on how cheery valve is feeling during christmas.

Black Friday is coming soon as well, they usually have a large sale then.

When there is a good sale (Summer or Christmas) most games are like 50 or 75% off their original prices.

I’m sure that when GMod goes down it will be like around 6 or 5 dollars/pounds.

Last christmas it was 75% off, and the valve complete pack was only 22€. I’d suggest you wait for it.