Homemade CS. Details on prep in my grow blog.
I have had more bad than good with C/S, it does work but I had so many misses with it that I finally gave in to try the STS.
I know it cost a few dollars but so do seeds.
If you have any friends that grow you might want to see if they would split on it with you it would be well worth it.
the smallest amount that I found was 25g of silver nitrate and 500g of sodium thiosulfate.
I make 100ml batches and there is enough there to make hundreds of gallons
I'll never need to buy more it cost me about 70 CAD for the 2 chemicals and about 70 CAD to ship.
If I lived in Toronto I could have went in to the store and saved on shipping. I would imagine most big cities would have a chemical supply store if you live close to one.
I'm still at 100% making seeds with STS.
My last plant gave me nearly 300 seeds. At about 10 dollars a seed, buying 15 seeds would pay for the chemicals.
The cost is what held me back for years but now that I switched I'm sorry I didn't do it sooner I would have saved a lot of time and money.
I'm not trying to force you but I am telling you you will not be sorry.
Best of luck in you future seed endeavors my friend!