Should I crossfire or stick to one card?

So my older brother's friend is selling a used Asus r9 270 2gb vram (non x) for $40. I asked him if he overclocked the card and if he did any mining on the card. He said no oc and only mined for a couple of days. 

Was thinking of upgrading from my HIS 7850 1Gb vram to that asus card because of how cheap it is. 

 

I know I can crossfire but I know the 7850 is lower the asus card by a bit. I looked at the benchmarks on the r9 270 which I can oc to the 270x marks if I wanted to and its about 15% faster than my 7850. If anyone can find crossfire benchmarks that would be great? 

 
I game on 1 1080p Monitor with one 19 in monitor for general stuff. 

 

1) Should I crossfire or stick to one card? 

 

2) Sell my 7850 so I can get money

 

3) replace the 550ti in my family pc(i3, 4gb ram, 500w psu) to the 7850

 

Specs

fx 6300 oc to 4.3mhz

asus m5a97 R2.0 mobo

8gb 1866mhz gskill ram

650w Rosewill Hive PSU 

I say just sell the 7850 and grab the R9 270. You will use less power compared to crossfire and not be limited to 1GB of frame buffer.

Technically the R9-270 is a Rebranded 7850.

From experience a 7850 Crossfired with an R9-270 or Vice Versa is a tiny bit overkill for 1080p The only time I've seen a Setup like that get destroyed was my Heavily Modded Skyrim Setup or Just loading up Crysis 3. But then again Loading up ENBs in Skyrim with a Crossfire Setup is Almost Broken unless you disable Depth of Field in that game.

To be Honest though 40 Dollars for an R9-270 I'd go for it. cause honestly you'll never find a Deal for that card like that EVER. and maybe down the line grab a Widescreen 2560x1080p monitor Crossfired R9-270s/7850s will handle that fairly well.

Buy the R9 270 and a second one to Crossfire it. Put the 7850 in the family PC. Sell the 550Ti and use the money for the R9 270s.

Thanks for the replies Everyone. I will try out crossfire when I get the card and see if its worth the crossfiring. I never crossfired before so this will a great experiment with my system. If I dont like it I can always either sell the 550ti or 7850 to get money into other things(new ssd would be nice on my system).