I simply cannot fathom the mindset of a person who buys the cheapest gun on the market chambered in comparatively expensive cartridges like .40 S&W or .45 ACP.
Given the cost of ammunition, especially .45 ACP, it won't take long for the ammo cost to eclipse the cost of the gun, and for someone who's putting a premium on the price of the gun, it would behoove them to put a similar value on the cost of ammunition, which, with regular practice, will eclipse the cost of the firearm.
Look at it this way:
Cost of a .45 ACP Hi Point carbine on Bud's Gun Shop: $269.
Cost of the cheapest .45 ACP practice ammunition at Midway USA: $17.79/50 rds.
It only takes around 15 boxes of shooting cheap-jack Tula .45 before you've spent as much on ammunition as on the gun, for a total cost of $535.
On the other hand, the price given for a 9mm HiPoint carbine is $271. Midway's cheapest plinking 9mm is $11.79/50 rds which works out to approximately 23 boxes of ammunition for about the same total price out the door.
Total rounds for the same setup:
.45 ACP: 750
9 mm: 1,150
So, for the same cost, with the 9mm, you end up with ~35% more ammunition, which, used properly, will make you a more proficient shooter.
Now, comparing the cost of the gun to the cost of the ammunition is, admittedly, kind of arbitrary, but it works as a pretty reasonable metric for comparing and assessing costs, and for someone who's budget-constrained in their choice of a PCC, the 9mm is all upside.
Long story short, buying a .45 ACP Hi Point is like buying a Yugo and then insisting on using racing fuel in it instead of regular unleaded.