Check the connector. Make sure the one you order has the connector you want. If it doesn’t, cancel the order while you can if it hasn’t shipped yet. You probably want one with a micro USB connector unless you have or want to make your own adapter.
You can try any micro usb cell phone charger down to 1A and see how well it works while you wait for your 2A charger to arrive. PiAware needs a bit less than 1A to run but most people suggest extra power to not be so close to the edge of the power requirements.
1A Power chargers are able to supply around 5V at lower power but as they get closer to their max power rating the voltage will drop. Once you get close to 1A the voltage will drop to less than 4.8V and bad things start to happen. The mostly likely case is that your 1A power supply will be enough. The second most likely case is that you will see the raspberry PI reset randomly from not enough power.
A 1.4A or greater power supply will never run into power problems.
It happens to be one from an old BT home hub, but any with a smoothed regulated output would do - maybe one from a modem.
The unit runs cool so is not lossey, 15v @ 1/3A will give almost 5V @ 1A (the antenna amp is 12v to 18v, that also matches the capabilities of the regulator.
(5.25VDC is within the USB spec and helps recover from the IR drop due to cheap USB cables)
Also of interest at Pololu are their buck/boost 5VDC switching converters –
https://www.pololu.com/product/2574 This is the one I use with Raspberry Pi systems. It takes a wide input range (3 - 30 VDC) and puts out a clean 5 VDC. Yes, it’s $15, but one of these will clean up a world of power issues.