Questions about entry level 5.1 receiver

Hi, I'm looking to setup a 2.0 system with future upgradeability to a 2.1 then 3.1 then 5.1 as money becomes available. I'm looking for a reasonably priced 5.1 receiver. I'm a total newb when it comes to this stuff and am not sure what I need for power.

I was looking at these 2 recievers:

https://www.amazon.com/gp/aw/d/B00INMG2TA/ref=aw_wl_ov_dp_1_6?colid=1KTW4Q1H0X8CP&coliid=I3KUXKOB1G42CZ

https://www.amazon.com/gp/aw/d/B00J30GXW2/ref=aw_wl_ov_dp_1_2?colid=1KTW4Q1H0X8CP&coliid=I28O4AYC08PEHO

For these speakers:

https://www.amazon.com/gp/aw/d/B00NOA58RS/ref=aw_wl_ov_dp_1_5?colid=1KTW4Q1H0X8CP&coliid=I3CR8BSOL3EMC5

This Center:

https://www.amazon.com/gp/aw/d/B0018QROM2/ref=aw_wl_ov_dp_1_3?colid=1KTW4Q1H0X8CP&coliid=I2U5SD33TILAW2&vs=1

And this Sub:

https://www.amazon.com/gp/aw/d/B0063NU3AA/ref=aw_wl_ov_dp_1_4?colid=1KTW4Q1H0X8CP&coliid=I3KRSNPRHSGND7

Thoughts and recommendations would be appreciated,

Thanks.