Shipping killed me too. I just bit the bullet and assumed the near one time cost to get enough amendment to amend roughly 10-20 bales which IMO can be construed as a lifetime supply. FWIW, the cost of the products @ Custom Hydro is dirt cheap and they have almost everything needed in one place, it just seemed the very best option for me. Also note, that most of these products are chems which require all sorts of safety precautions to transport and as such some of the shipping boxes have placards stickered on the sides of the boxes which alone will substantially increase shipping costs. If you're not in the lower 48, you might be able to find the SM-MP on Amazon and maybe skirt the insane shipping costs, otherwise you might be able to find a garden center in your country that can help.
I suggest you hold off for the winter to see how I fare in my grow with these products. This way you can save up, and if my studies lead me down a safe path, I will compile a BOM that I used with weights and measures of each, then you can decide if it's worth your time to get all or part of the things I'm using. IMO, the destination is what's most important, not the path we each take to get there.