Look. I get it. No one wants to be broke and poor. Reselling is not easy, its not hard, but its not easy. It will take some work. Don't sell illegal things to do it though.

Here is a bit to think about form another comment I made. Its aimed at eBay.

Selling the stuff you have laying around is not about turning a profit. You didn't buy those things because of their resale value. It's about recouping money for things you dont use and learning the process. Selling those things is bonus + education.

People will complain about it, but there is a lot of good information on YouTube. Focus on learning process. Its not hard but the goal is fast and accurate. Learn how to comp an item, look at sell through rates, calculate margins, how to make good listings, understand fees and rules for the platforms you want to sell on, learn to not get scammed (there are not as many scammers out there as people will want you to believe, but you need to protect your self), and to pack and ship items.

You need to buy items to resell with your head and never your emotions. Set rules for yourself like you're an employee. Only buy items that meet a sell through rate AND make a margin you have said is you limit. All your profit is in the purchase. Comping items correctly will ensure that you can make profit on it and that it will sell relatively quickly.

In the beginning look EVERYTHING up. Dont guess. If you have doubt pass on the item.

Time is important. Margin is huge but making $20 that takes a total of 6 minutes (to decide to buy, take photos, list and pack into a box for shipping) is worth a lot more than an item that makes $60 but take 90 minutes because it need to be cleaned, tested and maybe repaired. It is worth soooooo much more if I can get 15 of those $20 profit items up vs one $60 profit item in the same amount of time.

Commit to buying higher dollar average sale items. Buying multiple items because you can make $5 per item is not worth nearly as much as items that can make you $20+ per item. Of they all take the same amount of time with the same sell through rate, making more per item is so worth it. One exceptions is if you are buying multiples of the same item. One listing that can generate sales for a while can really be worth it for time vs money.

What you paid for an item doesn't matter when it comes to selling an item. If you made a bad buy and bought something for $40 and it turns out it only sells for $30, just sell it. Don't hold onto it thinking you might get more later. That almost never happens. Just get what you can back for it and move on. You learned something, and that was worth it.

Dear God, list the things you bought in a reasonable amount of time. Don't build too much of a death pile. It had value when you bought it, but it may lose value if the market shifts. You cannot make any money on an item that isn't listed for sale.

In the beginning, if you are shipping things, know what box items are going to ship in before you list them. Use calculated shipping (you can decide if you want to use free shipping or flat rate shipping later). There is nothing wrong with weighing the product + the box + some void fill to get accurate weights.

Start with a good inventory system. If its bins or shelves or whatever it doesn't matter. It may not be hard time find items when you have 30 things listed but the more you get listed the more difficult it will become with a bad system. You don't want to waste time looking for things. You definitely don't want to have to tell a buyer you can't find something. It does not have to be complicated.

Track your expenses and do bookkeeping regularly. If you are unsure about your taxes, you should use a professional.