You can choose any whole dollar amount between $1 and $2000 (or $200 when using a debit card). If you would like to purchase stock in a dollar amount that is higher than $2,000, it will have to be broken up into separate transactions.
We are currently working on updating our cashiering platform to make it easier for our customers to purchase stock in larger dollar amounts. Thanks for sticking with the current process in the meantime!