However it may be unsafe if you don't know alot about hair extensions as you can get ripped off as you can't see the hair in person and may not know the exact colour, length, amount and quality of the hair you will receive.
As I have over 12 years experience working with hair extensions I have compiled a list of tips to buying wefted human hair extensions on eBay:
Always make sure the item description describes the weight of the extensions as well as the length. 200g of hair is enough for a full head. You should pay no more than £150 for this amount unless it is of European grade (£670+)
2. Is it human?...
Make sure the description states 'human' or you could receive low quality and cheap synthetic hair which cannot withstand heat and will melt as well as look shiny, fake and cause potential skin irritation.
3. Double Wefted or Double Density?...
If the description states double wefted or double density the hair will be too thin. Hair that comes double wefted are two rows sewn together to create the thickness required.
However ALL hair should come double wefted anyway. Therefore do not be impressed with sellers who say they sell 'double wefted hair' - be wary.
Additionally some sellers cut through stitching so as to double their profit margins stating 'that is how they received it from the manufacturer'! This results in you being left with only half a head of hair worth of hair extensions.
The lengths in inches of the weft are usually even numbers: 8", 10", 12", 14", 16", 18" etc
Therefore if a seller sells hair at 15" it may be actually only 14" but they have exaggerated in the hope you will not notice so they can sell the piece at a higher price. Therefore always measure the hair when you receive it and if it does look short, send the seller a polite request for some new hair of the length stated in the advert also explaining your observations.
Alot of sellers advertise their hair as Remi or Grade A. However most of the hair I have seen on eBay appear to be Grade C. Don't be confused by the ever growing list of 'impressive' words sellers use to describe adequate hair. Don't pay insane prices unless it is described as INDIAN VIRGIN REMI as it does not tangle because it is cuticle correct. As mentioned this should cost roughly £200+
If you're unsure what colour to buy visit a hairdresser or check out YouTube for people with a similar hair colour to the one you require or have similar complexions. You may need to blend two different colours. Make sure you don't presume by looking at pictures on an eBay listing - as looks can be deceiving
However if you do get the wrong colour or length arrange a refund or exchange with the seller. Don't leave negative feedback. Don't get para - it's probably a mistake. However if it happens more than once with the seller try writing a letter of complaint suggesting they take some more care when sending items. If you feel they'll make the same mistake again, don't buy from them again.
Always read feedback - not just the first page either. Find any negatives and read them so as to find out what other buyers have been unsatisfied with. They may hint at problems in one particular area. If more than 10 people have issues alarm bells should be ringing and you should avoid. Additionally as eBay have disabled sellers from leaving their customers with negative feedback it allows customers to leave more honest appraisals of sellers. Use this to your advantage and determine for yourself if the seller is someone you'd like to purchase from.