You can purchase a single report from each CRA. Some other options include:
If you have your Experian report number from when you pulled your reports before, you can go to their website and towards the bottom in the middle it will say "review report again", click that and enter your report number and other information and you'll see a current copy.
Otherwise go to TransUnion's online dispute and go through the steps to get a report to use for disputing. You don't actually have to complete a dispute, but can view your report.
If you've been denied credit in the last 60 days, are unemployed, and under some other circumstances you can get a free report from the CRA. If it is for denial of credit, you get a report from the CRA the creditor used.