We have low water pressure in that a shower feels like a drizzle. To solve this it seems to me that you could put one of these sealed pressure tanks in hooked to you city water for water supply, but with that pressure system you could run your water pressure up to 60 lbs or more if your plumbing could stand it.
The sealed pressure system tank doesn't cost much, some of smaller ones little over 50$. But expectedly the bigger, more water volume would probably be best. But I think the size is regulated by the amount of water supplied in a certain amount of time.
They seem easy to hook into you water system. Just like making a splice, one pipe in and one pipe out. The only thing you might have to put some solenoid to turn water supply on and off, when tank reaches desire pressure, but those are basically inexpensive.