I live in China so the struggle is finding a good enough battery that will ship to China. If you have any, could you send over some other batteries that would suit me better. Im looking for a 10s4p setup and a reasonably thin battery as i have a drop through setup so I dont have much clearance. I am aiming for something like 20+ Km range and between 35-50 Km/h for speed. If you could point me in the direction of some good batteries that would be great. Obviously i dont want to spend too much money on a battery but i think $250 would have to be the maximum. I’m not opposed to getting a smaller battery however i like the idea of that larger range. The speed though would need to be the same so a 10s battery.
If you live in china you live in the best place in the world to get some 30Q cells stupidly cheap. I would pick up a pack made with them and go from there 
I’m not entirely sure about the legitimacy/quality of the battery you posted. It says it’s a LiFePo battery but according to the stats it seems more of a Li-ion pack. 150$ is not a bad price for a pack including BMS but I personally wouldn’t buy it. The manufacturer doesnt state what cells and BMS it is using so it’s hard to check these claims.without buying and testing the battery.
If you’re looking for 20+km range, then you’d need about 200+ Wh and with 35-50 km/h you wanna go 8-12s with a max discharge of about 20A at least. The most cost effective would either be LiPos or 12s2p 30Q’s (at minimum). Are you willing/able to go DIY?
I’m not against building a battery however it seems rather challenge for a noob like me and also when you add the costs of the additional equipment required like a spot welder I think it is just better both in cost and ease if I buy a premade battery.
Alright, I just found a battery person that makes batteries specifically for electric skateboards. They don’t offer a 10s4p battery but the 10s3p samsung battery seems quite good. That is the one i would get if i was to get any of them. https://www.alibaba.com/product-detail/Wholesale-Electric-skateboard-18650-lithium-ion_60710609454.html?spm=a2700.details.maylikehoz.2.5ec815f4NvD5df