Listing your goods for sale is easy if you know the classification for them according them to the eBay policy. If you sell goods such as bulk consumable, tools and hobby supplies they are classified as general items. The best thing about general goods on Ebay is that the market is year round.
The changes in the market demand will be small. The real problem occurs when someone sees a gap in the Ebay market and starts selling in volume because soon others will do the same and before you know it the market is full of the same item being sold. This will cause market saturation and prices will drop over time. Always check for other items that are similar or are perfect substitutes, they can damage your sales and cause you to lose revenues. If competition becomes tough, wait and list other items that have fewer people selling them.
Sometimes it is a good idea to sell used or re-conditioned products on Ebay to improve your profit margin because they can be sold for less. When prices are low, you can grab some of the existing client that are buying from other stores. Do not compromise honesty so be truthful about the products flaws and imperfections if any. The last thing you want to do is send a worn item to a buyer who was expecting something pristine and perfect so be forthcoming about item quality, or risk negative feedback and a bad reputation.
General goods is a niche on Ebay that will produce similar results to an offline business. The effort you spent and great customer service will play an important role in the success of a merchant. Sales will not be large, but it will be steady and giving you a good income over a considerable period of time.
There is only the slimmest of chances you will be a millionaire next week if this is your first time on eBay. Make your initial goal to earn money just as a supplemental income. Diversify, diversify, diversify because you don't want to depend on one item, or even a few items, to generate your income. It is good to offer many different kinds of products for sale so that your overall income will not drop if the sale of a single product does drop.
The demand for general goods on eBay will always be present. Start by setting up your own store in eBay. Once you've built up a reputation for having what everyone needs, when they need it and at a fair price, you will have a bright future as a seller of general goods.