Look in your reloading book for primer size. The 10mm I believe is a large pistol off the top of my head (but double check). The 5.7 is probably a small bit again double check.
Cheapest bullets will be cast lead. Can be found for around 60-70 per 1k. But lead can be Smokey and you might not be allowed to shoot it indoors (depends on range). Next cheapest is plated which is around (80-120) per 1k depending on brand and weight. Is cleaner than lead but you can't push it to extreme or the plating could be damaged causing bad accuracy. Of course next is fmj and you'd have to look prices up. Obviously fmj is the best bit generally most expensive.
As for bullet weights....that's up to you really. For 10mm I use either 180gr or 220gr plated bullets and havemt had an issue yet. But they do make different weights for different applications. I generally stick to the weight the gun was originally and is most commonly found in. Ie 115gr for 9mm, 230gr for 45acp ect. I do use other weights such as 147gr for subsonic 9mm for my suppressor. See bullet weight is hard to say which is best. Just go with what the gun was designed around or you have been shooting.
As for 5.7 reloading....I have no clue on it and haven't looked really. Last time I did I don't think anyone was really reloading for it.