you can find on mining specific threads, but in my opinion if you only have small capital to mine bitcoin I think it's quite difficult to get profit, because of the high difficulty level and a little block reward will not be profitable for solo miners, that's just my thought

so you might be able to mine other altcon as an alternative where you can adjust your spending budget and calculate the amount of profit, you can mine IDENA without having to use mining equipment even you can sell it into bitcoin and it's free, you can visit the signature link that I use below