Which altcoins are best for small payments in terms of transaction costs and speed?
RaiBlocks, which is now rebranded as Nano, is by far the best option for this. Nano is specifically designed using a block lattice system which allows transactions to go through almost instantly
https://www.reddit.com/r/CryptoCurrency/comments/7jj68u/raiblocks_speed_comparison/.
This system also utilizes very little computing power which allows for nearly zero transaction fees. No need for mining as well.
RaiBlocks/Nano is currently the best option for a scalable everyday currency.