I would like to share my finding for Aliexpress. This is Aliexpress search by image from Pricearchive.org.
Look at this page https://www.pricearchive.org/same/4000544376719. There you'll find other Aliexpress sellers of the item you need. Often finds sellers of exactly the same product even better than Aliexpress itself. It's possible to search through all the product pictures at once. It's a great way to buy cheaper exactly the same product from another seller.

How to use
Find the product you need on Pricearchive. For example, this one https://www.pricearchive.org/aliexpress.com/item/4000270993878. Click on the red button "Find other sellers by image".

Here is a screenshot.

Check the price history for the item you want to buy. Copy the phone page address at Aliexpress and paste it on https://www.pricearchive.org or use their browser extension for Chrome or Firefox. Pricearchive is the best Aliexpress price tracker website which saved me a lot of money. Then check the price chart and you'll see how the price changes, is the discount real or not, at what price it is better to buy and when.

Wilfem:
How can one do all these with the AliExpress Android application?
Because that's the one I mostly use.

AliExpress Android application is a separate application.
Press share button at the top of the page in this app. Then press 'Copy'. Open Pricearchive.org in your browser and paste all that was copied into the search field on Pricearchive.org. Press search and see the graph.

Yeah, the price on the package.

The best way for expensive orders is to ask the seller to specify a low price. Then there will be no need to pay extra.

Nobody buys in these stores? Let's share ideas, coupons, gift cards.

I suggest sharing all known ways to save money when shopping on Aliexpress, Amazon & Ebay in this thread.

I'll start with best three known to me services that have saved me several hundred bucks.

1. For Aliexpress
Pricearchive - https://www.pricearchive.org/ - best Aliexpress price tracker which I know. They have price info for about 80 million products from Aliexpress.

How to use
Find any product on Aliexpress.com site and paste its page address into the search field on Pricearchive.org
or
Install their official extension for Google Chrome
https://chrome.google.com/webstore/detail/pricearchiveorg-shopping/ebbilkbochjjalheallpnblfdhkfjjmp
or Firefox
https://addons.mozilla.org/en-US/firefox/addon/pricearchive-org/

Check the price history for the product and avoid overpaying. You can track your product and/or buy it when the price is minimal. They send price drop email alerts.

See the image below to understand the idea of this service.


I really love this service because thanks to their graphs I always buy at the lowest price.
Tip from me.
With this service you know the minimum price for the product. So you can write to a seller on Aliexpress and ask him to sell at this price. Sometimes it works! Try yourself.


2. for Amazon
Keepa - https://keepa.com/ - Amazon price tracker, a little better than camelcamelcamel.com

How to use
Install their browser add on for Google Chrome
https://chrome.google.com/webstore/detail/keepa-amazon-price-tracke/neebplgakaahbhdphmkckjjcegoiijjo
or for Firefox
https://addons.mozilla.org/en-US/firefox/addon/keepa/

Check the price history before buying on Amazon. See the image how it looks like


Check the price history for the product and avoid overpaying. You can track your product and/or buy it when the price is minimal.


2. for Ebay
PicClick - https://picclick.com/ - Search eBay Faster

How to use
Open any product on their site and see 'PicClick Insights' section. Click on 'More'.

I like this site because it shows a lot of insights and a lot of similar products from Ebay.

You can tell me thanks if I saved you a hundred bucks.

Know how to save more? Let's write everything in this thread.

The main thing is not to forget about the money, otherwise the phone will go back

What is your experience, is everything good with phones, how long do they work?

demospain:

There is black,brown nd oxford colour in shoes.
Do u want red colour in shoe or sneaker?

I would like to see a photo of red shoe if it exist.

What colours are there? Is there red?

The first photo is the best

it happens that you get bored and you want to play something else

Played Fortnite, currently Dota

beautiful sneakers on the last photo

Cvesta:
Redmi Note 7 vs Redmi Note 6 pro . Which is better to buy please ? User reviews needed on battery life and durability

Redmi Note 7 of course. This phone is newer.

What kind of yellow stick does he eat on the second last photo?

I like the color of her hair. They are bright as the sun.