I was down at corvus in a cent and found that the local base was willing to sell me a large port missile (I forget which one) even though my ship couldn't mount it. No other large port weapon or mining beam was available even though I had the cash for them.

Seems to me that if your ship can't mount the darn things, you shouldn't be able to buy them.'

Since you always have the option to buy a new ship, and to stockpile weapons, I have to disagree.

While I don't believe the ability to purchase weapons that can't be equiped should be disabled, this is certainly a point of confusion for newer players. "How come I can't equip X weapon?" seems to be a common question.

There could be some indication in the buy menu that shows that there aren't any open ports for that item, or some such thing. This would be a good consideration for when the station display gets a makeover.