There are a number of reasons to go with better quality indexable insert holders, I believe I mentioned previously they usually have a replaceable insert seat, a anchor pin/replaceable threaded sleeve, screws, etc. The hardware is much better. This means if something breaks, you usually do not loose the whole holder, Also these parts are interchangeable so the same CCMT size tool holder will often have the same parts be it left, right or center cut. That way, I can rob parts from one I rarely use for another if needed, as opposed to having a lot of oddball holders.. Speaking to a few other people that have the cheap import holders, and the switched to more name brand holders (and inserts), they have noticed a difference. You also may select holders in higher quality holders for the ones you use a lot, and less expensive for those used less frequently. So in my case my daily users are the CCMT Kennametal and Seco WNMG, less frequent I may use something like a TMX or what I consider a mid quality holder. A good holder, especially with replaceable parts, may be the last holder you buy.
There are good inserts, and there are alo a lot of bad ones. There also can be fakes. I have tried a few odd name/no name ones, at least for me they just do not last and break quickly. On something like the CCMT in a 32.5X size which firs 5/8" holders, I have found that the Kennametal CCMT09T304-SM IC907 (32.51) is a great all around insert it works in many materials and holds up well. I have purchased from both of these vendors, they appear to be the same.
http://www.ebay.com/itm/ISCAR-CCMT3...-SM-IC907-Carbird-Inserts-10pcs-/192270850902
http://www.ebay.com/itm/10-inserts-CCMT-09T304-SM-IC907-ISCAR-CCMT-3-1-SM-IC907-/292035875576
If youre budget is really limited, this vendor seems to sell a number of decent quality holders/inserts at very reasonable prices. At hese prices, I would not buy used online, they are often pretty mangled, but I will buy something new if the price is right.
http://www.latheinserts.com/5-8-SHANK-LATHE-TOOLING_c164.htm
On inserts, there are so many types coatings, breakers, etc. it pays to read up and find what works for you and stick with it. I did a lot of research, and have a fair understanding, but you can quickly get lost in the zillion types of inserts out there. I look at the profile, coating, and indicated materials it is indicated along with the type of cut.