My friend is running a pathfinder game and I was wondering how much it would cost for my character to have clothes that mend themselves should anything happen to them (getting stabbed/ripped, catching fire, ect.). He said I could have them but we couldn't figure out how much they'd cost.
You want to buy a Sleeves of Many Garments for 200gp. This item, when you put it on, lets you transform your current garments into any other nonmagical clothing, which will always be clean and mended unless you specify otherwise. If your new clothing gets damaged, you can fix it by removing and re-equipping the sleeves.
Let me also talk about how you'd go about pricing a custom magic item to produce this effect.
You want to look at http://paizo.com/pathfinderRPG/prd/magicItems/magicItemCreation.html which describes how the DM can assign prices to custom-made magic items. Be warned that this generic framework does have some loopholes, so it's important to sanity-check the final result of any calculation. Your DM has the right to adjust prices up or down, or simply to veto any item created with those rules.
You're creating an item based on the spell mending. This is a cantrip, which counts as a spell level of 1/2 for purposes of magic item creation. If you use a caster level of 1 (the minimum), it can mend objects weighing up to 1lb. The cost for a "continuous mending effect" would be (2000gp) * (spell level 1/2) * (caster level 1) = 1000gp.
You might argue that there should be a discount because this magic effect doesn't let you mend just anything, it's limited to only affect your clothes. Or you might have to pay more, because the mending spell technically only affects objects weighing up to 1lb per caster level, and your pants and boots probably weigh more than that.
(In fact, we know that a very similar item costs 200gp, so in this case there should be a steep discount!)
This effect would still be pretty slow: the mending spell repairs 1d4 points of damage every 10 minutes.
Note that, for the same 1000gp price (and again with DM approval), you could get a ring of mending which would allow you to repair anything. (Again limited to items weighing 1lb.) You would probably have to concentrate on the repair process when using the ring, whereas the built-into-your-clothes version would operate on its own.
If you're looking for fun silly spell effects, consider getting a ring of prestidigitation for the same 1000gp, which lets you "slowly lift 1 pound of material", "color, clean, or soil items in a 1-foot cube each round", "chill, warm, or flavor 1 pound of nonliving material", or "create small objects, but they look crude and artificial". Which is better: the power to magically repair your clothes, or the power to magically clean them?
If you're a spellcasting class, you can probably take the mending or prestidigition spells as cantrips, which lets you use the effect at-will without paying money for a magic item.
Finally, consider the hat of disguise for 1800gp, which lets you change your appearance by illusion. This lets you look like your clothes are cleaned and mended, and it also lets you look like someone completely different, at will.
Dan B's answer is probably the best rules based answer you're going to get, but I would like to take a different tack. Rather than start by looking at what the rules say, you should start with how useful this item will actually be to your campaign.
In most campaigns, things like hygiene and the state of your clothes don't really come up, both because they're easy enough to deal with if you actually care and because there are more interesting things you can do with your time. In such a campaign, self-mending clothes provide literally no benefit. This is a bit problematic, since the rules for determining item cost assume that the item will actually help you in some small way. In this type of campaign I'd do one of two things:
- Give the upgrade away for free. It has no mechanical benefit, so I don't have to worry about them unbalancing things, but they are an interesting roleplaying addition and that is worth rewarding. I might also consider giving the other players similar, mechanically useless, but flavorful items. Some RPGs, like Numenera, actually do something similar as part of character creation, with each character getting a random item that could either add flavor or serve as a plot hook, but has no real mechanical significance.
- Most, mundane, clothing goes for between 1 and 10gp. The three exceptions, in the SRD, are doctor's clothing, noble's clothing, and royal clothing, which go for a whopping 150gp, 75gp, and 200gp respectively. The doctors's clothing actually gives you a +2 vs contact diseases, so I won't be discussing them, but that might help put things in perspective. For the remaining two pieces, the SRD claims the price increase is because precious metals and gems are worked into the clothing, but in a world as magical as D&D it would be reasonable to assume that the aristocracy would want basic convenience enchantments on their clothing. In such a case, you could rule that Noble's get a self-repair function with their clothing, while royals get self-repair and self-cleaning. You'd then just charge the same price for different cuts with the same enchantment.
Conversely, if you're playing in the type of game where this sort of thing will matter and your clothes will repair fast enough for it to be relevant, you could either follow the enchanted item guidelines or treat it like armor, with the different types of armor telling you how fast it will regenerate (and giving you an idea of how much it will benefit you).
Finally, all of this assumes you're talking about generic clothing. If the clothing is inherently useful (like, say, a vacuum suit) then an auto-repair function becomes much more valuable and should cost an appropriate amount. Possibly the equivalent of a +1 enchantment, if it's important enough.