Per the DMG, pgs. 116-117, Magical Research and the Manufacture Potions/Scrolls.
Potions
The brewing of potions requires a caster having achieved at least 7th level. At 7th level, the services of an alchemist are required. The caster can brew potions without the assistance of an alchemist at 11th level.
Scrolls
The scribing of scrolls requires a caster having achieved at least 7th level. Materials (ink, quills, vellum, etc.) are available and purchasable. Scroll preparation can take place concurrently with item recharging.
Ink costs 250 SP per bottle; each bottle is sufficient for one spell (regardless of level). Quality vellum is 25 SP per sheet and reduces chance of failure by -5%. Seven spells may be scribed on one sheet of vellum.