It's just not a good idea to keep more than one fish in a bowl, since the level of waste buildup is bad enough for one fish already. Not to mention the low levels of dissolved oxygen in a bowl. I honestly suggest getting a betta if anything, because they are adapted to low levels of dissolved oxygen--although you would still have to change the water daily, if not multiple times daily, to keep the waste levels appropriate.
As much as you may not want to hear this, if you want more than one fish, it is just way better to get a tank. It's like living in a tiny apartment and deciding you want more than one dog---it's a mess waiting to happen.
Luckily, because of the moneymaking in desktop aquariums, there are cheap starter kits for 2-5 gallon tanks at wal*mart that can fit on a desk, that come with everything. It's a lot less water changing for you to do in the long run, because it comes with a filter---and and you will definitely have better success with your fish mortality rates.
Some good fish groups to get for these would be neon tetras,(or any other small tetra) rasboras, guppies, or some female bettas, if you want to have more than one betta---they are more docile and can be kept in groups often without trouble. good luck, I hope this helps you
!