Hi Bryan, welcome to the Forum.
My take is you already stuck a fork in it, and should probably continue with that line of Pioneers for the 5.0 speakers. The are a good start for a entry level Home Theater system, but the Sub is to be avoided. By the way Audioholics rated these Pioneers the best HT speakers for less than a grand as I remember. Product of the year a couple years back!
The only knock I heard on the Pioneer SP‑FS52 was they were a little short, and needed small platforms to bring them up to ear level. Folks who put them on small boxes said that improve the experience a lot.
I have a pair of Pioneer SP-BS22-LR (from the same family of speakers) for my home office, and their great for that purpose. Best Buy & Amazon sold thousands of this line a few years back, so the used market should have lots of them, in decent shape, for a reasonable price. If you can be patient, you should be able to grab the SP-C22 and a pair of SP-BS22-LR for the rears. The real kicker will be buying a decent Sub (eventually 2?) but there are lots around; and again if you are patient the OEMs have specials and "B" stock clearances.
I'd start with a receiver. Right now at accessories4less.com, there is a Denon AVR-S920W for $290 and you can look around the Web for a coupon for a discount, free shipping, etc. I have it's older sibling => an AVR-S900W. I'm very happy with it and the AVR-S920W is even more capable. This unit will allow you to grow or migrate into an Atmos system later if you want to, but it will be the kick ass center for you 5.1 system in the meantime. I certainly wouldn't spend more as you need to save it for the Sub(s). And the Denon AVR-S920W will let you connect a second sub if you want to add another later as your financial situation improves.
Like lovinthehd, I too would head for the Sub next leaving the SP-BS22-LR for the rears until later (or if you stumble across a steal of a deal).
Just for grins I just searched and got a Pioneer SP-C22 Andrew Jones Designed Center Channel Speaker in stock at Amazon for $99 and a pair of Pioneer SP-BS22-LR Pioneer Loudspeakers for $129 with free shipping. Best Buy has them in stock at the same price too. Maybe you won't have to wait??
IMHO the real homework will be to get you the right deal on a Sub. But the boys here certainly can assist you there.
