Udimi is among the most trusted marketplaces for solo ads buyers and sellers.
A solo ad is basically an email ad that can bring traffic and leads.
If you do not have an email list, you can rent a vendor's list of subscribers and send your email ad to them.
Udimi has been around since 2008 and it's homepage stats were added in 2016.

For buyers

How to buy
Go to Find Sellers section and use filters at the top to find a seller who suits you best.

Review Results
Everythings is pretty simple here: name of the seller, short bio, price per visitor, percent of Got Sales ratings and ratings from all solos this person sold on Udimi. At the bottom you can see latest rating this seller got. Pick any seller and click the box.

Review Seller’s Profile
At the top of profile you will see seller’s country and city, local time, all ratings and awards. You can directly message the seller via button or use options to add this person to favorites or to block.

Check Average Stats
Below the order form you will see average traffic stats from the latest 30 solos of this seller.

Read Ratings from Buyers (most important)
All ratings you see here are from Udimi solos only & negative ratings are non-removable.
Positive ratings on Udimi are divided into 3 types:
1. Good rating from a buyer who got at least one sale
2. Good rating from a buyer who doesn’t track sales or has free site
3. Good rating from a buyer who didn’t get any sales

Place the Order
When you are ready to buy, jump to the order form.

At the top you can select number of visitors you need and the date for mailing. Below you can see a slider as alternative way to select number of visitors. Maximum number of visitors depends on the seller and clicks availability on selected date.

Select Filters
Below visitors slider you can pick traffic filters that will be automatically applied on your solo.
Base filter is always included on all orders and can not be turned off.
Prime filter is optional feature and costs 3¢ per visitor. It saves you more money and it's recommended to turn it on, but that’s up to you.
Only top tier - you’ll get only traffic from wealthiest countries. This filter adds 10¢ per visitor and you should take a look at average percentage of top tier traffic this seller has. You can see it on the map.
Only mobile - you will get traffic only from mobile phone users and tablets. This filter adds 10¢ per visitor.
No mobile - you will get only desktop traffic, including laptops. This filter adds 10¢ per visitor.

Put in Your Link or Swipe
Ok, now put your link in the next field:
If you have ad text, it is even better. Tick the “I have ad text box” and insert it in text area.
The system will automatically save your ad text or link in Ad texts area. On the next order it will automatically insert your previously used ad text. Your ad text must have at least one link. It can have as many links as you wish, but to one website only.

Define Timing
If timing of the solo is not very important for you, then keep this checkbox on.
But if mailing time is super important for you, then uncheck this box and select exact start time you require.

Now you are ready to order. At the bottom you can see your order total and average time it takes for the seller to accept new order.
Click Add to Cart and you will see your shopping cart with your order inside it. If you wish to buy few solos at once, go back to Find Sellers area and add all solos to your cart. When you are finished adding your solos to the cart, just pay for all solos with one payment.
Cart button is always visible at the top menu.
Click Continue to complete your order.

For sellers
Before you can start selling, you have to buy at least one solo or get Prime status. This is needed to lock your seller profile to your PayPal / Credit Card info in order to fight fraud and make impossible for banned scams to return to Udimi under new name.
Go to Settings > Seller Setup and turn Seller Mode ON. You’ll see a window with all options.

Prime Status
Prime is an optional paid package on Udimi that unlocks many useful features of Udimi, like optin tracker and landing page builder.
It directly saves you money by filtering additional 7% of useless clicks comparing to base filter.
Price: Monthly - $29.95, 3 months - $85.36, 6 months - $161.73, 12 months - $287.52

Affiliate Program
You will get 15% from all solo ad sales from all your referrals.
You will get 25% monthly from all Prime members or 50% monthly from all Prime members if you are Prime yourself.
The commissions can either be spent on Udimi or withdrawn to PayPal, ePayments or TransferWise.
All your referrals will get $5 gift code instantly after registration via your affiliate link. This code can be used on any $70+ order.

Link: Udimi