Should I upgrade my PSU?

[mah Boi]

I am thinking to buy a Graphics Card, GTX 1050 Ti Mini... I have a 240-250W PSU, and its recommended PSU is 300W.

 

[Lutfij]

More than the wattage, we'll need to know the make and model of your PSU as well as it's age. Aged PSU's will have capacitors outputting less power due to wear and tear. Furthermore, it'd help us to know of your full system's specs.

list them as:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

 

[geofelt]

You are likely OK.
Cards such as the GTX1050ti mini do not need an aux 6 pin power supply and will run on pcie slot power.
That is a maximum of 75w, leaving plenty in most cases for the cpu and peripherals.
I would go ahead and buy.

If it is a very old unit where the wattage is not mainly for +12v, then reconsider.
The label on the psu should give you the watts or amps that can be delivered to +12v.