Maybe it's just a cultural issue...
OP, generally in the USA, when we're posting an amount of money that includes the cents portion, we put a decimal between the dollars and the cents. Thus, your $15000 would be written $150.00

btw, $150 is a smoking good deal for those windows; usually something like that would run at least $400 to $800 each!
For what it's worth, generally, the cost of windows is calculated by "united inches" - simply the length plus width added together. While your windows are somewhat tall (I've seen much longer), they're not that wide. Using object in the picture to estimate the size (I'm guessing the seat of the chair is roughly 16 to 18 inches), I'm taking a shot at 18x65. There's no way on earth that one, or even all of them, are worth $15000. Windows under (high 90's) united inches aren't *that* special. (However, having had some high-pressure window salesmen come to my house to give me estimates, I discovered that there are many companies more than willing to charge four or 5 times the actual value of windows; they'll even finance them for you.) After 2 high-pressure salesmen, I checked a local lumber company; I could order them myself or have a local contractor do it for a small percentage of what the "factory direct" company was quoting.
edit: and I just shopped around for prices; while I couldn't find an exact price, I did find that the price is indeed per united inch at several places, and if you go over 99 united inches at one place (and 101 at the other), it's an additional $5 charge per united inch. Your windows haven't even hit that threshold where they're considered "special."