At the beginning of the game, you will probably have very little money.  You can keep getting free supplies from the mayor until you have completed the Gaffer's Buggy and placed it in the georama.  He will only give you one of each item, but at least it is an option until you can make some money.  Don't forget to visit the mayor after each floor of the Divine Beast Cave.


Be sure not to trigger the event at the Gaffer's Buggy until after you have placed Pike in the georama.  If Pike is not there, the Gaffer will try to put up his own sign, and will injure himself in the process.  This will greatly reduce his inventory.


View the event at Claude's house in the morning, so you can get the Candy as a reward.  You will need it in Matataki Village.


If you use Powerup Powder from the inventory screen rather than from the Weapons section of the menu, your weapon will go up a level, but will retain the Abs it had gained in the previous level. 


If you do a status break on a character's original weapon, you will get a synth sphere from it, but it will not disappear.  It will merely lose the + levels it had gained.


Back floor keys are usually hard to come by, but in Queens, you can buy the back floor keys from Ruty.  This makes it a great place to level up weapons.  The back floors not only provide tough enemies for experience, but also frequently contain gems, which can otherwise only be obtained by trading fishing points, or buying them from the Fairy King in the Dark Heaven Castle. 


In Muska Lacka, try to complete and place Brooke's house as soon as possible, because he runs a shop.  It will be more convenient to shop there while working in georama mode than going back to a previously completed area to get the supplies you need.


If you have the maximum amount of money the game will allow, buy Gold Bullion and keep it at one of the storage facilities.  That way, you can continue to make money, but when necessary, you can sell back the Gold Bullion for the same price you paid for it.  Some of the Mystery Seals in the dungeons will increase your money.  However, the increase is relative to the amount you have.  If you consistently have a small amount with you, the increase will not be very large.  If you are carrying 30,000+, the increase will be huge.  Each time you reach the max, buy more Gold Bullion and store it, as long as there is room, but try to keep a reasonable amount of money in inventory.


You can trade fishing points for items, and then sell them to make money.  Holy Water costs only 5 FP, and sells for 60.  Mighty Healing costs 15 FP, and sells for 150.  The Holy Water is a better deal, but it takes more inventory space for several Holy Waters than for a few Mighty Healings, so you will have to decide which way works better for you.