A friend of mine is looking to buy a very inexpensive telezoom and asked for advice.
I’ve made a list of the most inexpensive telezooms I’ve been able to find, but I have no idea how well (or poorly) they perform, as I have no experience of them.
Canon EF 75-300/4.0-5.6 III
Canon EF-S 55-250 4-5.6 IS
Sigma AF 50-200 F4.0-5.6 DC HSM OS
Sigma AF 55-200/4,0-5,6 DC
Sigma AF 70-300/4.0-5.6 DG MACRO
Tamron AF 55-200MM F/4-5.6 Di II LD Macro
Tamron AF 70-300/4.0-5.6 Di LD Macro
They are all very cheap, but the Canon 55-250 IS and Sigma 50-200 OS are a little bit more expensive then the others, so I would expect them to be a little bit better.
Does anyone have any experience of any of these? Any of these one shouldn’t even touch with a stick? Thanks in advance for any advice.

You've confirmed my first thoughts. The EF-S 55-250 is the only (or at least best) option in that price category. Now I have to convince my friend 
