Online arbitrage explained: anatomy of a deal alert

Online arbitrage is retail, not trading: you buy a product where it is cheap right now and resell it on Amazon for more. Whether that works is not decided by the price gap but by what is left after every Amazon fee. That is exactly what a Delta alert calculates – here is one real alert, taken apart line by line.

What online arbitrage means

You use a price difference for the same product between two places. You buy online – in a web shop or on another Amazon marketplace – and you sell on Amazon, often through Fulfilment by Amazon (FBA).

It only works when three things line up:

• A real buy price you can actually order – no "was" price, no estimate, shipping included.
• A sell price on Amazon the product really sells at.
• Demand. A wide spread on something nobody buys is worth nothing.

Spreads come from shop promotions, sudden price drops, and from the fact that the same product is often priced differently on Amazon Germany, France, Italy and Spain.

How Delta finds deals

Delta is a deal group for Amazon sellers on Discord (the group itself is German-language). More than 40 source monitors compare shop prices and Amazon marketplaces with the Amazon sell price around the clock. When a monitor finds a spread, it calculates the profit after fees and checks the hit against fixed rules. Only what passes every rule is posted as an alert.

A real alert, line by line

This alert was posted in #deals on 15 October 2026 at 02:53 (UTC). Buy on amazon.it – sold and shipped by Amazon itself – and sell on amazon.de. A check on four test accounts showed the product could be listed without any brand or category approval. We leave the product name out on purpose – that is what members pay for.

How to read it:

1. Spread: €124.09 between buy and sell. That is not profit yet.
2. Profit per unit: after Amazon's fees and shipping to Germany, €66.21 is left for every unit sold.
3. Margin: €66.21 out of a €439.00 sell price is 15.08 %. Margin tells you how much room you have if the sell price slips.
4. ROI: €66.21 on €314.91 of capital is 21.0 %. ROI tells you how hard your money works.

Every alert comes with the buy link, the Amazon listing and the prices it was calculated with. You do not have to trust the numbers – you can recheck them before you buy.

The rules an alert has to pass

Every hit runs through the same rules before it is posted. If it fails one, it is not posted:

• Margin after all Amazon fees≥ 8.4 %
• Profit per unit after fees≥ €8 (buy price < €70: ≥ €5)
• Sold on AmazonDE · FR · IT · ES
• Sales evidence: at least 30 reviews or a sales badgerequired
• Star rating, where known> 3.7
• Buy price from a real, in-stock offer incl. shippingno estimates
• Buying on Amazon only from Amazon itself or the official brand storerequired
• B-stock, used, refurbishedonly in #warehouse-wie-neu

At 15.08 % margin and €66.21 profit, the alert from 15 October clears both minimums of 8.4 % and €8 by a wide margin. Proof of sales came from Amazon's "50+ bought" badge at 4.4 stars.

What an alert is not

An alert is a calculation at the moment it is posted, not a promise of profit. Prices and stock move all the time, on the buy side and on the sell side. So before you buy, check for yourself:

• Is the buy price still live and the product in stock?
• Are you allowed to sell this brand or category on Amazon?
• Does the capital fit your budget – just over €315 per unit in this example?

The buying decision is always yours.

Is the membership worth it?

Only if you actually buy. For scale: membership costs €79 a month regularly, or €49 for the first 20 founding members. One unit sold from the alert above, at €66.21 profit, would already have covered the €49 founding price; two units (€132.42) cover the regular monthly price as well. That is one example, not an average – but it shows what a good alert is worth.

Benefits, onboarding and cancellation are on the membership page (in German).