ShipScript has been an eBay Community volunteer since 2003, specializing in HTML, CSS, Scripts, Photos, Active Content, Technical Solutions, and online Seller Tools.
I think it depends on how much record-keeping you have in mind, the depth of your product line, and whether you plan on growing.
For a hobby level of a few hundred listings each year, the data entry of individual items into an accounting program is not cost effective and is easy to continually put off until later.
If you are just trying to summarize your sales and expenses for your tax return, then PayPal is a good source of data. I run all my expenses (ebay fees and postage) through Paypal, so at the end of the year, I can run a detailed report on PayPal that I can sort for gross revenue, sales tax, shipping, and fees. I print out the detail report for my records and then provide only the totals to my accountant. The only data missing from that report is cost of goods and business overhead, which can be tallied separately.
PayPal will export to QuickBooks, so perhaps that is one argument for using QuickBooks if you plan to turn over a lot of inventory. Some people just use a spreadsheet.
I think the only way to make inventory management reasonable is to maintain your inventory in a spreadsheet or accounting program and then export that inventory to eBay programmatically or though a spreadsheet upload to File Exchange. Otherwise, data entry becomes a headache of duplicated effort.
When inventory is separately maintained (whether in a spreadsheet or QuickBooks), a seller can apply cost of goods and expenses to a single item or product line to see if it is profitable, and that makes sense only on a larger scale. The seller must additionally apply reductions to inventory, by either recording individual sales or by making journal entries to reduce inventory. That much bookwork does not make sense on the small scale.
I have a mixture of both. My corporation has a full-blown inventory and billing system. We track incoming and outgoing inventory and costs of goods sold and purchased and have a customer base with billing and shipping preferences along with quantity discount levels. My hobby eBay sales and PayPal sales are pushed into this once a year as PayPal summaries because I don't want to track all those individual little sales, nor do I want to re-enter them into my bookkeeping program.
I would recommend that you post your question on the Selling forum to see what other sellers are using there. Be sure to ask what level of sales they push through their method because that is most pertinent to the answer, as I hope I have outlined above.
https://community.ebay.com/t5/Selling/bd-p/selling-db
