FX-6350 worth it?

I'm considering making a small form factor budget pc, as i don't think my laptop performs quite as good as i would like my transportable pc to do.

If i'll be making it, I will primarely use it for gaming, and i was wondering if the almost 30$ extra for the 6350 was worth it over the 6300, if not, i'd be able to have enough money for upgrade my GPU on my main computer as well, and use the curret GPU from that on this budget PC.

Small form factor? I'm assuming you mean mITX or MicroATX. Those aren't really possible with an FX series part. There are no good mITX or MicroATX motherboards out there for the AM3+ socket. I wouldn't trust them with the lower TDP of the 6300 let alone the higher TDP of the 6350. 

The 6350 is just a higher binned 6300. You could easily get the same speed with an OC 6300. Just get that and save the money. That being said, you really need to go ATX if you wanna get an AM3+ part. 

MicroATX or mITX you need to get an FM2+ part or go Intel Socket 1150. 

Well i've read some fairly good reviews on the Asus M5A78L-M, So i'd assume i would be able to make a decent budget pc with that?

You'd be better off with a FM2+ platform - AM3+ doesn't have any small form factor cases that I know of designed for use with the FX series CPUs; they're all re-badged 700 and 800 series motherboards from the Phenom II era. I had an experience with the best of them (Gigabyte GA78LMT-USB3) and whenever I'd try to oc even the most mild of overclocks, it would throttle down to 3.5GHz and voltage was all over the place. The more I tried to OC, the more it throttled, and passed a certain point, it voltage spikes would get worse (LLC didn't help much) and so would throttling, down to 3.2GHz. Entirely possible that it was a bad board, but you get the idea.

The FM2+ platform will also give you can upgrade path to Steamroller when AMD releases a streamroller Athlon, or a cheaper A8 Kaveri APU. As it is, the Athlon 750k provides an excellent bang for the buck, is a capable gaming CPU, and the savings would free up some budget for a better GPU on your other rig.

As for your question - paying more for clock speeds on an unlocked CPU is almost never worth it UNLESS you are NOT overclocking.

Based off what I've found by googling it, that motherboard only has a 4+1 powerphase which isn't the best for a power hungry CPU. Plus overclocking would probably be completely out of the question.

It is a decent motherboard but it really isn't designed for the FX series processors. It has the same 4+1 power phase design without any heatsinks on the VRMs. It is definitely not designed for OCing and should only be used in a system with very good ventilation to keep those VRMs cool. IE not a tiny system. 

It may be fine for the 6350 but I wouldn't be surprised if you got some voltage throttling or component failure. The 6300 would be pushing it kinda close as well. 

Small form factor on a budget you need to go FM2(+) or if you can spend a bit more Intel. 

Would i be able to play BF4 on 1080p with low settings with the 750k?

Spend the extra $10 for the Richland 760k and pair it with a good GPU and you'll be able to play at 1080p on high. 

Most games aren't very dependent on the CPU. Crysis, Metro, and other poorly optimized games as well as gaming at 1440p+, require more CPU horsepower but for most games, especially at resolutions of 1080p and below, you don't need to buy an expensive CPU. If you are just gaming the 760k will be more than adequate. 

The 760k isen't actually avaible in my country, so it'll be kinda hard to get...

You'll be fine with the 750k then. The 760k isn't that much faster. You could OC the 750k to similar speeds most likely. 

So a 750k + an eVGA gtx 760 with acx will be able to handle BF4 on medium to high on 60fps?

Well, according to a newegg review:

This CPU is very fast for it's price. I overclocked it to 4.1GHz with the stock cooler on it and in my MSI A75-MA-E35 motherboard and it runs games very well. Battlefield 4 on ultra settings in single player and medium/high settings in large multiplayer maps.

This would be more helpful:

https://www.youtube.com/watch?v=qIT9uLDjZcg

Basically, the Athlon can handle BF3 at ultra well over 60FPS, if it isn't GPU bottlenecked.

Yes.

I would go with an AMD graphics card, if you want to play BF4 Multiplayer. Mantle should help a lot with CPU usage. I would get the 270x, MSI or Asus

Yeah well, i currently have the 760 in my current PC, i want to upgrade that, so i'll probely get a more powerfull one for my main pc, and then use the 760 from that in this build.