After spending hours and hours searching every nook that Detroit had to offer, I was tired of picking up huge amounts of ammo because enemies guns that get left around get converted to said ammo if you already own the gun (obviously). 
Since bodies and weapons stay around in the environment for a very long time (360 version), I started making trips back and forth to the local gun merchants.   
Sell a shot gun, go back and pick up another, and repeat. 
 
I must have earned over 10,000 doing that, which of course bought me two more praxis points!  This might be kinda ruining the game pacing... but I hate knowing there are badass abilities locked up inside me that I can't get to!!!  ;D

@hoossy:

You got the points while exploring and doing stuff I assume? If so don't worry getting more points simply unlocks more possibilities for you, it does nothing to game pacing.

As for carrying guns back and forth you are kinda wasting your time. There is a ton of money available in the game if you explore properly anyway.

Heh. After picking up like the 5th or 6th shotgun in Detroit and remembering that the arms dealers let you SELL stuff in this game, my mind quickly went to work. Currently I'm past the first boss, have the praxis kits from the LIMB lab bought and still have around 25,000 credits on me.
 
It seems like I have a ridiculous amount of XP aswell for this point in the game, unless it's actually not too outrageous (I have about 68-70k XP).

@Tennmuerti: I'm assuming he bought them. Praxis points are 5,000 credits a piece at the LIMB clinic.

@BakerTheZombie said:

@Tennmuerti: I'm assuming he bought them. Praxis points are 5,000 credits a piece at the LIMB clinic.

Oh that. Didn't think about that since I had over 10k when I got to the Limb clinic anyway.

@hoossy: It seems like you can only buy a max of 2 praxis kits each time you switch hub cities, so money is rarely an issue. Unless you're going around buying weapons and then dropping them later or something, you should never be that strapped for cash. I never was anyway, and I didn't resort to any crazy "gun farming", as you call it.