I would do some research to see what the retail prices you can find on all those items as the stated ARV seems high for a lot of those items. If you can prove different and lower prices, your tax would be subject to the amended ARV and not the stated ARV. This may or may not be worth it to you, especially if you're worried about getting more attention on your return from the IRS. You might also consider selling some of those items you don't want or need to help pay for the taxes
If your income is relatively the same as last year, simply just add the value of the prize to the line showing Adjusted Gross Income and then look up that amount on the tax tables. This would give you a good idea