Display Junction, is probably the the only source carrying almost all and any type of folding Promotion, Demonstration or Display Tables.
Life span of a table that you need for any project. Do you need it just for few weeks or months. May be you could factor in higher cost for a Reusable table with fresh set of graphics.
How much weight is right weight as it may directly effect the longevity of the product, though not a must but slightly increased weight may mean better material being used in manufacturing of the product.
Ease of use. Is the table easy to install as difficulty of installation is directly related to damage to the product. Watch this to see screen promotion table
Do you really need a shelf ? Most shelf systems are light weight good for no use for show sake. A good shelf system would suresh increase weight as well as price.
Decide what is the table top size, you require for your activity.
Quality of printing is as important to you or price is more important.
Strength of hinge is most important factor , when chosing from a range of aluminum frame based tables.
Door type hinge in any aluminum system would not last very long, even if it is securelg rivetted.