It could go down to $170 or even maybe $150 without there being a problem with the game. I believe base price either allows: +50%/-50% or +80%/-40% for Market Price. I haven't look TOO closely. Glad I'm not heavy into HTS, but that Gasoline crash hurt . . . and the Oil slide isn't doing me any good either. :?
It looks like demand fell by 4B suddenly and has held constant at the lower level. Or, maybe the 14B demand was a sudden spike. Can't really tell, the graph cuts off.
No, base price is a FIXED number whose apparent function is to determine the range market price fluctuates. It would have some relation toward the cost of production, but it has always been a FIXED, unchanging number (barring game updates).
Anyway, Navy Missile Interceptors on FB show the bottom range (consistent surplus): Base Price: $9.9M Market Price: $4.4M
Looking at an average of the cost of my corp supplies, they are reducing, which could be partly the use of less of product as well as low prices of things. Checking various demand graphs, seems to me corps are using less.