How to obtain full value games?

Same way you obtain any other games outside bundles, buying them after checking if SG has bundlified them yet or not.

buy games that aren't heavily discounted. ¯\_(ツ)_/¯

Alright, thanks

Any game outside this list is considered non bundle for now. It gets updated regularly, so you can always check before you buy.

https://www.steamgifts.com/bundle-games

As heilurmes said above, you can always check before you buy anything just by typing the name into the "Create a new giveaway" page - or, if you use the sgtools "deals" page you can filter to only show full value games.

Thanks everyone for clarifications. It helps a lot