Paper Mario Limited Inventory

Hey everybody! I've been casually using RPG maker for a while now, and I've searched far and wide for a certain plugin, but I haven't been able to encounter one. I want to make a game with elements similar to the old Zelda games (Limited wallet size that you can increase a couple times by doing side quests) and a limited inventory with very few slots (very similar to Earthbound and Paper Mario). I don't want key items to count towards the inventory limit though- only the more strategic, battle type items (potions and bottled lightning and things like that). It would add such a great strategic element to my game of needing to ration items and being unable to just save up a billion coins to get a million potions.

Yanfly can't do what I need it to, and neither can the mr trivel limited inventory.

Please Help!!!

EDIT: Its for MV

If you don't want key items to count towards the limit, I'm guessing you want two item categories.
Regular - which would have a limit.
And key items - which would not have a limit.
That is a smart way to do it, in my opinion. Having required key items fill up the limited slots is rather annoying.

That is exactly what I'm looking for. haha I made an account on here just to request this specific plugin or to ask for ideas. I don't have any javascript experience... Its actually the very first plugin I would ever use- possibly the only one. Everything else I can do just through variables and switches.

Out of curiosity, wouldn't you be able to do that with a variable? Like, say your items are limited to thirty. Create a variable for an item count, have it increase with every item you pick up/purchase. Then, if the variable hits thirty, run a conditional branch that states you can't pick up anything else until you drop something. It would be a bit of a pain to implement in something big, but I think it would be doable?

I guess I could- How would I make It so that the variables change using buy/sell?

That's a bit trickier... I would suggest this plugin (http://sumrndm.site/switch-shop/), but that only sets it so buying an item turns a switch on.
It's a little unintuitive, but you could potentially set each item to activate the same switch when purchased. Then, set that switch to a common event as an autorun trigger. In the common event, add the variable, and then immediately turn the switch off so you don't soft lock the player, and so you can use it again.
Honestly, this is just my best guess: I've never tried to implement this, and I wouldn't know how you could limit the item consumption through shops, or how selling could factor into it. If I were you, I'd do away with default buying and selling systems entirely and just event your own using the item select screen (unless, of course, it's too late to do that). If anyone else has any suggestions, I'd be open to hearing them.

Edit: Sorry, what I said far below by itself won't be enough to work for you, as you also want to increase and upgrade the limit. Should have realized that sooner, but I researched further and there were plugins for this on MV, but from the last posted replies in those threads, they say they have bugs in them and no longer work.

The variable method would work if you just gain the items through events and not the default in-game shops. It is easy to control that with the events in the editor itself if you upgrade once, more times gets more tricky and require more than one extra conditional branch, but I will explain below how this can be done, otherwise the solution above witch the switch shop plugin, should hopefully work for you, and perhaps someone else can provide a plugin that just works very simply.

If you want to know how the variable can change through buy/sell there are different possibilities. If it is a key item that increases the stock of other items, and it does it once, you can check if that item is in the inventory, otherwise it can be done through enabling a switch and checking through switches. Both would also require conditional branches and the more times the items can upgrade the more branches you will need, but, while possible, this can get trickier to keep track of in events, and a plugin that works would be far cleaner, easier and better.

You would also need the variable to check if the limit has been reached or not, and if it has not to be able to add anymore of the same items. If you choose to do this through events, using more than one variable for checking different items may make more sense.

@JAWAH

If it is just some of your items you want this limit feature for, Yanfly plugins can do that actually. You need Core Engine.

See here

http://yanfly.moe/2015/10/09/yep-1-core-engine

Try this plugin:
https://forums.rpgmakerweb.com/index.php?threads/limited-inventory.59965/