i dont know if dry form of sodium nitrate is cheaper option for me.
Dry form is WAY cheaper than NeoNitro.
NeoNitro costs ~$26 for 2000ml on Amazon, which I think in total would raise a 100G tank by about 158ppm Nitrate: 2000ml / (100G x .1261 per the bottle). This comes out to $0.16 per ppm
I use the same brand of Sodium Nitrate listed above (although I'm sure I could find cheaper), but is $27 per 400 grams. According to the Planted Tank Calculator linked above, 400 grams of sodium nitrate would raise a 100G tank by about 650 ppm Nitrate. This comes out to $0.04 per ppm, or 4x cheaper than NeoNitro.
When mixing you own you not only get to have more knowledge about what's in it, but better control over potency -- all for a fraction of price.