I am An Avid Doll Collector and Have Been For Many Years.  Ebay is My Number
One Spot To Look For Dolls. To Help Buyers I Have Made a List To Help You Buy
Quality.  This Is How I Go About Choosing The Seller & The Decision of Making
a Purchase:

#1  Serious Sellers Are a Number #1 Priority With Me.  They Must Have
Knowledge of What They Are Selling.  Full Descriptions With All Details
Is Truly a Serious Seller...Questions Are Always Answered Thoroughly.
Photos Are Clear...No Fuzz or OddBall Objects Included Within The
Photo...Baby Displays Are Perfect in The Background.

#2  Type of Doll Is Another Need To Have:  Let Us Just Say That They
Have Vinyl Stated Within Description.  Well There Are Many Types
Of Vinyl is it Soft or Hard? Is It Silicone Vinyl? Or What?

#3 Flaws If You Are Buying a Used One Be Sure To Ask If There Are
Any Flaws At All...Whether it is a Mark or a Scratch or Anything
Else...If it is Not Mentioned Ask The Seller.  Be Sure To Look At
All Photos Carefully.

#4 Photos Can Be Deceiving Many Sellers Show a Reborn In Their
Photos But It is Only a Non-Painted Kit For You To Create.  Some
Times This Also is Just For The Head, Legs Arms or Body Suit.

#5  Reborns Look For What Kind Of Kit They Used.  They Should
State The Artist Sculpt and The Artist. 

#6 Reborn Buying, I Personally Feel They Must Belong to a Guild
If You Wish For a Truly Real Looking Baby. 

They Must Have Details Of What Type of Paint Used Genesis Is Permanent
& Recommended, Size of Needle Gauge For  Hair Rooting, Other Details
Such As Are The Lips Glossed, EyeLashes Glued or Handrooted?,
Magnetic Pacifier Or Not?, What The Baby Is Coming Home
With, Props Should Always Be Mentioned As Just
Display Props Only. 

Also Be Sure To Look With In Their Description For What Type of
BodySuit Was Used & If There Is a  Tummy Plate Included. Doe
Suede is The Best Type Of Body Suit In My Opinion. What Type
Of Mohair Was Used? I Prefer Angora.  Also Be Sure They
Have Stated  The Color As Photos Can Show Different
Colors.

What Type of Eyes Were Used....There Are Many That
Do Look Real....I Do Like Secrist The Best. What Color
Are They? & One Final Detail...Look At The Photo
Carefully...Do The Eyes Look Straight & Even?

Photos Were They Taken in Daylight, Flourescent Light, Etc?
This Helps Determine On How The Baby Truly Looks, As Most
Open Their Reborn Within Natural Or False Light...This
Can Make The Baby Appear Differently And Not As
You Saw On Photos.

Most Importantly Was This Reborn Weighted With:
Glass Beads, PVC Pellets, Or Something With
Quality?  Sand is Not Quality. If This Is
Not Stated As Seller Before Bidding or
Buying.

#7 Dolls Should Have an Approximate Year or The Exact Year
Stated Within The Description If Antique or Vintage.

#8  Pay Attention to Shipping & Handling Charges.  It is Perfectly
Fine to Charge a Packaging & Handling Fee, But Within Reason.

#9  Insurance -  I Highly Suggest You Opt For It.  This Way The
Doll is Covered & Protected During The Shipping & Packaged
Correctly.  This Also Helps To Ensure Your Doll is Delivered
To You. Beware If Your Package is Being Shipped UPS
Then Insurance is Already Covered...Do Not Pay
Extra. USPS on The Other Hand Does Cost Extra,
So Be Sure To Add That On When Considering
The Price of S&H.

#10 Sellers Feedback Ratings -  Check Them Out.  Anything
Within The 90-100% Is Not Bad...They Cannot Please
Everyone.  Things To Look For at Negatives & Neutrals
Are Repeated:  Items Not Received,  Received Broke,
Not As Described, Poor Packaging, Etc.   Sometimes
You Can Verify a Seller's Reputation By Checking
The Buyer's Who Left The Negative or Neutral's
Feedback Rating By Simply Checking The
Buyer's Feedback.

Tips For Sellers:

#1 Be Clear On What You Are Selling With Details As I Mentioned
To The Buyers Above.

#2  Answer Questions ASAP and Thoroughly.

#3 Always Have The Option Of Insurance Or Make It Part
Of The Sell.

#4 Never Worry About 100% Perfect Feeback,  As We Buyers Know
You Cannot Satisfy Every Single Customer....Just Try Your Hardest
& We Will Still Buy!

#5 If You Are a Reborn Baby Artist Please Always Mention The
Sculpt That You Used As This Makes It Tons Easier For Us To
Find If We Are Looking For a Specific One.

Thank You For Reading My Guide & I Hope It Has Helped You On
Your Buying Decisions!