well then it's ok.
I haven't used APM, but I thought, need of extra channels for each of it's functions.

I am using APM 2.6, ublox gps and 900mhz telemetry with FS th-9X.
5.8ghz FPV works fine with 900mhz telemetry and 2.4GHZ radio. Better you use circular polarised antenna.
if you invest something on your radio get a 9 channel. otherwise 6 ch is good.

well,  There we have an experienced user.

Great, are u using the original apm 2.6?, @ linked

 And thank u so much for all Ur help guys... 

Apm work better with 9ch rc and use 433mhz telemetry. I use the same no issues if signal interference yet. Don't go for 900mhz as our mobile companies use that frequency for communication.!

3DR introduced this two telemetry kits for coping with laws in different country, We can use 433MHz or 900MHz depending on what is allowed here.

Yes I'm using the 433mhz one,  I'll invest on a better radio later on( maybe in 3 or 4 momths)

Well I saw a deal on eBay.com for an apm for 1$ it was an auction.
It was from a top rated seller.

It would help if you posted a link. I believe that if it seems too good to be true, it probably is. 1$ is unreasonable, unless it is liquidation of defective pieces.

yes dude it is true, if you are so lucky and no one but you bid on it before it ends, you can get it for 1$ !! (which probably won't happen as it is an APM for sale and people all around world will be watching it ) .
And this is how I sourced all my parts, dirt cheap !