Tell him that you SE by checking a combo list by hand 

Quick simple method for paying less for steam games.

You'll need: a VPN ,  (preferably) steam account with unlocked market.

1) Change your store region to any of these countries: Armenia, Azerbaijan, Belarus, Georgia, Kyrgyzstan, Kazakhstan, Republic of Moldova, Tajikistan, Turkmenistan, Uzbekistan, Ukraine or Russian Federation.

2) Buy cs:go / dota / tf2 , etc. skins that can be sold on steam market cheaper. ( You can buy tf2 keys from keyvendor or somewhere similar for 1.55$, instasell them in steam community for 2.22$, and get 1.94$) So you bassicaly get  1.94$ for 1.55$ to your steam wallet.

3) maximize your profis by waiting for the next steam sale. (Which will sadly be in 133 days as im writing this)

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Examples of game current game prices in steam's market: 

Rocket League: 251 pуб (3.5$~)

Rust: 309 pуб (4.5$~)

GTA V: 10 Eur ~

You get the idea ;]