What's wrong with Valve

Its been like that for a looooooooooooooooooooooooong time mate

What do you mean you can't do anything during the sale?

Yup, it is all in the FAQ: https://support.steampowered.com/kb_article.php?ref=6088-UDXM-7214

Cant you just buy a super cheap card for like 3 cents and it should count?

It says "The account must have a successful purchase older than 30 days, but not older than a year. " so it shouldn't be a problem at all.
Unless you really don't buy any games

Welcome to 2016! It's been like this for a long time. There have even been threads made here by others who were mad about it too but those were long ago when it was still considered news. Now we have all grown to accept it and moved on. Maybe you should be more active?

Thats just the crowning part of account limitations valve imposes on accountS. Chat limitations are pretty severe i heard. All the stuff around steam guard and s. Authentificator. I've had to enter pointless codes all the time. More than once thought about just disabling it.

STAWP.

I had the same problem awhile back - need to be bought from you from the steam store within that period of time of you get that popping up. If you're just entering keys from elsewhere then it doesn't count as buying from steam.