Also, all the scrolls shown in the Dungeon Master's Guide contain a single spell. There's not actually any rule that limits scrolls to a single spell (see page 237 in the Dungeon Master's Guide). To create a scroll of multiple spells, combine the spells' base costs to determine the scroll's creation time and XP costs. If the multiple spell scroll is abandoned, the whole expenditure is wasted.
One advantage to creating a scroll with multiple spells is that you have to use only one action to get out the scroll during an encounter. Once you have the scroll in hand, you can read any spell it contains. DMs should feel free to set a reasonable limit to the number of spells you can search through on a multispell scroll before you have to use an action to find the one you want. I recommend a maximum of seven spells. If a scroll contains more spells than that, it takes a move action to find the correct one. As spells are used from a scroll, the writing that stores them vanishes from the scroll, which can make the remaining spells easier to search.
