I started playing in mediumticker (Manchester City) again a season ago. At the moment I only select a squad because a lack of time.
Now I look at my transfer amount today and it’s only 203k. Some ticks ago it still was more than 1M. I know because I wanted to buy a player but hadn’t enough money.
Is this a bug or is there a reason for this decrease? My financial situation hasn’t changed much.

Your budget will go down as your money goes down, or if your fixed expenses (wages + investments maintenance) go up. Doesn’t look like a bug (just had a quick look), but if you keep an eye on it and still feels that something is odd please let us know.

Transfer budget now is 0. However I have 13M total budget which is regular. How is it possible to build a team like that?

You need to reduce your investments and try to sell some players to start with. Also hire some free players either to use or re-sell later. When I joined Santos in FastTicker it had only 6M balance and 0 in investments, I had to immediately sell a few players and luckily the total wage was low so I wasn’t losing money when playing home. In a few seasons I had a decent amount of money to hire better players, but I suppose I was not even close to the richest teams in the Brazilian league…

When you sign players from the free transfer list, do they still have to pay their transfer value or are they actually free?

They are free. Your transfer budget may still show a lower value after the transfer because now the player’s wage is part of your fixed expenses, and that is taken into account when calculating how much you’re allowed to spend on transfers.

Just to make it clear (some people have asked me this before), the transfer budget is not something separate from your team’s money balance, it is just how much FROM the money balance you are allowed to spend on player transfers.