Is there anyway to submit an item from your inventory to the market? If so, please tell me.

I think only gamemasters can submit, but hey, I don't have a clue.

Go to your deactivated items and choose an item you want to sell. Click edit and set the price you would like to sell it for.

Yes, you can.
Go to your deactivated inventory and click on the item icon you want to sell, it should give you an option to type whatever amount you wish in there, type in there whatever you want to sell the item for and click "update"
then your item should be in the market up for sale.

Okay. Thanks for the wanted information.