Accounting for computing merchandise purchased?

How do I compute the total cost of merchandise purchased for the year? I do not want the answer I just want to know if I am leaving a part out when I am computing this for the year
Merchandise inventory = 31000
other noninventory assets = 120400
total liabilities = 35500
Capital = 101650
withdrawls = 8000
sales = 212000
sales discounts = 3250
COG sold = 82600
sales salaries = 29000
rent exp selling space = 10000
store supplies exp = 2500
advert exp = 18000
office salaries exp = 26500
rent exp office space = 2600
office supplies exp =800 Supplementary records include]
Invoice cost of merch purchase = 91000.
Purchase discounts received = 1900
Purchase returns & allowances = 4400
cost of transportation in = 800

You included a lot of information that can be ignored. Focus on the last 4 items in your list: ending inventory, inventory purchases, purchase discounts, returns/allowances, and freight.

91,000 Purchases
(1,900) Discounts
(4,400) Returns/Allowances
800 Freight
-------------------
85,500 Net Purchases

The cost on the books for purchases has to be the cost you actually incurred. That's why you decrease the amount by any discounts you took or any returns you sent back or any allowances the vendor gave.

Freight is tricky, as sometimes it is expensed separately instead of flowing through to COGS. Honestly, it depends on what kind of inventory is involved.

If you just want to compute merchandise purchased, it's as follows:

Invoice cost of merch purchase = 91000
Purchase discounts received = (1900)
Purchase returns & allowances = (4400)
cost of transportation in = 800
Total purchases $85,500

Cost of transportation IN (sometimes known as carriage inwards) is part of purchase cost of merchandise. Transportation OUT (aka carriage outwards or delivery charges) are selling (part of SG&A) expenses.

I have attached an excellent chapter on merchandise purchase for you.