Thank you guys for your replies, really appreciate it!
Also if i might add, what are the kind of things i have to take note when getting 3rd party lens, be it used or brand new?
Many of the third party lens manufacturers make lenses for multiple DSLR bodies, so you need to check that e.g. a Tokina/Sigma/Tamron and so on lens, has a Canon/Nikon/Sony etc. mount.
If you buy a used lens, just make sure the vendor has the original box + packaging (most likely then just one previous owner) as well as both original lens caps (front + rear), and it is in obvious good/immaculate condition, but most importantly you have to TEST IT on a DSLR e.g. I have a new EF-S 18-55 IS lens that will not go below f/5.0 but if you held it in your hand or used it at 55mm @ f/5.6 (it's max. aperture) you'd never know that it had been knocked off a coffee table < 2 feet to the floor but the aperture blades no longer function correctly.
This past summer I sold a 70-200mm f/4L IS USM lens to a photographer and he bought it within 2 mins having tested it and paid me 900 euros for a 2008 (date code) lens, as it was the 4th one he'd seen that week for sale (all the others were cheaper 800-850 euros) but to quote him: "they were all junk in rag order". Mine was pristine - bought new in 2011 as a Retail demo model - and did not have a single scuff/scratch on it, was regularly cleaned with a Lens Pen + always had a 77mm HD filter on from day-one.
That's another tell-tale sign when buying a used lens - does it have a filter attached and if the seller says that the filter is not included (also means that they look after their gear + purchase decent filters).
wow, thanks for the detailed info. really appreciate it.