Need Kitty Help

I can't offer much help but sometimes animal shelters will have a very low cost vet, and usually a very low cost, if not free spay/neuter program.
 
Maybe you could also call a local vet if this is something to be concerned about, and if this is common. Then maybe at least you could get a little insight about what it could be.  Sorry I wasn't more help!

Are they positive that it went on accident and it wasn't marking or going there b/c there is something it doesn't like about it's box? 
 
I have a cat who is perfectly litter box trained.  Sometimes though she pees in a bed when she gets out of it.  I think she is either marking it so the other cat won't sleep there or her litter box isn't clean enough for her even though I clean it daily.  If I put a cover on their box, she will most definately find somewhere else to go.  Just a thought, try taking the cover off the box if there is one.  It could also be marking.  Just my opinion.  It could also be something medical but this is just what has happened with us.

In my early teens I raised 3 kittens whos mom had been hit by a car when they were just 2 weeks old.
 
The only thing I can recall that might apply to this situation is that at six months old one of the cats started their first heat.  They weren't peeing like this but I wonder if one of the cats is starting to come into heat, maybe that is somehow affecting her awareness about holding her pee? 

Too bad you don't live in Indiana.  Our Humane Association is handing out coupons this  month for $5 spay and neuters.

I second the heat idea as a possibility.  It could also be a UTI as cats don't scream in pain or anything like that.  They don't cringe or moan or anything, they just go pee somewhere else than the litter box.  My sister's cat had a UTI and never knew anything was wrong except for the peeing outside of the litterbox.

I can't believe I didn't think of this earlier.  Have her tested for urinary crystals or bladder stones.  I had a kitty with FLUTD (feline lower urinary tract disease). 
 
Does it seem like she is clueless about the peeing, or that she is straining at all? 

If they are ffeding food that has a high ash content, they could very easily have cystitis. Once this is cleared up (whatever it is) make sure they feed a higher quality food.

Thanks everyone []

The lowest spay they can get is just over $100 per cat. Ya - thats low cost.

I'll get them to maybe get a few more (different) litter boxes and see what happens. Maybe even different litter types. I wasn't there when it happened, but they said that the cat was laying comfortably, and when she got up, there was a puddle in the bed (like, 6 inches in diameter - she had definately been holding it for a while). She had peed while lying down.
The kitten does use the litter box though. I went there yesterday to assess the situation, and when I went near the litter box, both kittens decided they needed to go.

g33 - my fiance thought it could be related to heat as well. They're both just about due to come into heat soon.

I'll try to find out how much it'll cost to get a urine sample tested for a UTI. Does anyone here know how to collect a urine sample from a cat? lol [8D]

And they're feeding Nutro (indoor kitten) right now. Haven't checked the ash content but at first they were feeding Purina cat chow [8|] I convinced them to switch, and I think it's an improvement.

For collecting a urine sample, see if her vet might give her some Nosorb (it might be possible to order some online..not sure) it's little plastic pellets that you put in a litter pan (they'd have to isolate her for an evening with the pan) so that cat will feel like it's going on litter, but the pellets don't absorb any of the liquid.  That way they can just pour the urine into a container[]