[3.5e] Treasure Roll

[Merk]

In the campaign I'm running right now, one thing I'm considering is doing away entirely with the gp system that D&D typically uses (the PC party is a crew of pirates and so is constantly finding treasure, in units that don't correspond well with gold to boot). So a friend of mine told me about a system called "Profit Margin" inspired by some RPG that I forget the name of. I took a shot at developing a system that could work like that:

For each session, each player makes 3 "treasure rolls"; this can be done before or after a session or during downtime. In order to make a treasure roll, the player must first state the desired item (e.g. a +2 Flaming Longsword) and then roll. A treasure roll is, simply

1d20 + 1/2 x Character Level + Profit Margin

*Profit Margin is an assigned score that represents a character's savvy in trading.

The result is then checked against the DC of the item, and if it is successfully met, the character acquires the item. If not, the character does not gain the item.

The DC is determined from the below table.

Item Type: The type of item desired.
Minimum Level: States a minimum character level required to obtain a type of item.
DC: Difficulty of getting item.

Mundane Item DC = 0; does not count towards treasure roll limit
Poison DC = DC of Poison
Alchemical Item DC = DC of Alchemical Item
Magic Item Less than 1000 GP DC = 15
Weapon DC = 15 + 4 x Bonus; Min. Lv = 3 x Bonus
Armor DC = 15 + 3 x Bonus; Min. Lv = 3 x Bonus
Armor/Save Bonus DC = 15 + 2 x Bonus; Min. Lv = 3 x Bonus
Ability Enhancer DC = 15 + 5 x 2 Bonus; Min. Lv = 3 x Bonus
Ability Inherent DC = 20 + 5 x Bonus; Min. Lv = 5 x Bonus
Scroll DC = 15 + 2 x Spell Level; Min. Lv = 2 x Spell Level (Cantrips are 1/2)
Wand DC = 20 + 2 x Spell Level; Min. Lv = 2 x Spell Level
Artifact DC = Ad Hoc; Min. Lv = Ad Hoc

For example, Elias is 8th level and has a Profit Margin of 4. He wants to get a +2 Light Crossbow, which is a DC 23 item according to the table. He rolls a 17, adds 4 from his level, and 4 from his margin, for a total roll of 25. Since he beat the item DC, he receives the +2 Light Crossbow.

What do you think? How does this fare as a replacement for the gp system? How should I award and scale Profit Margin (or should I use something else)?

[Siosilvar]

Your Profit Margin should be something along the lines of 1/2 Appraise ranks, if it merely represents the character's ability to purchase. If you want to include buying power, then something along the lines of +1 per major treasure (varies depending on level!) should suffice.

[Milskidasith]

It doesn't scale well enough (though your math is listed wrong; you have it as +4 to the DC per +1, but you have it as bonus/4, or a +4 is a +1 to the DC). By level three, a character should have a +1 weapon or armor, but it's exceedingly unlikely they get one (1d20+1+Profit Margin) means you get it... very rarely.

[Dante & Vergil]

Seems good, but maybe it can use some work. I'll keep an eye on this.