You can't replay areas. Money can be a problem. Use no more characters than necessary, open all chest, cap as many monsters as possible, sell every thing you don't need. --- I come from the nowhere, I go to the no place and here I am.
One extreme method is available, but it's not that practical. You can use the heirloom system to grant items to other parties in other tales. If you are completely stuck and can't progress, you can start a different tale, play that tale and then sell an item with an ability attached to it to the shop. Your other party would be able to buy that item and hopefully make progress with new equipment. That way you don't lose all the progress you've made, you just kind of put it off for a bit.