Ok... how you can get hats on tf2? Simple!
Step 1: Find a weapon
Step 2: Sell that weapon for 1 scrap
Step 3: Sell that scrap for 2 weapons
Step 4: Repeat!
If you use these 4 steps you can get a hat and you will be happy!
Or you can just get lucky and find a heavy hat.

Now... these are the weapons I would use or prefer when being a heavy.
Weapon 1: Tomislav
Weapon 2: Family Business
Weapon 3: Eviction Notice
This is what I would use as a heavy. But thats not on my heavy.
Weapon 1: Iron Curtain
Weapon 2: Family Business
Weapon 3: Fist
These are the weapons I would choose if you wanted your heavy to look good. Also the 3 weapons at the bottom are what I use. Use these weapons!