In a market I used to run a startup in, $1000 was a very common point in our industry at which individuals with purchasing authority and a credit card (i.e: the people we wanted to convince to hit Buy Now) needed to go up to the next level for expenditure approval.
$999 (or in this case $995) meant they could whack it on their card and not go through approvals process etc.
Obviously this price point will vary with industry and time, so suss it out in your industry (if it is applicable at all).
Completely agree with this, $5 can be the difference between a middle manager swiping a credit card and a tough conversation with a GM and procurement (ever had to procure AdWords before?)
And, although in these days of Stripe & PayPal, etc, it's not such a big deal, the ability to take credit cards for bills is the difference between being paid immediately vs. waiting 6-9 months for the invoice to be paid because you're not an Approved Supplier and Purchasing needs to get a waiver to pay you.
$999 (or in this case $995) meant they could whack it on their card and not go through approvals process etc.
Obviously this price point will vary with industry and time, so suss it out in your industry (if it is applicable at all).