In my 7x8 mini lathe I most often work with round bars or machine screws, but also with larger odd size and shape raw materials.
Switching 3 and 4 jaw chucks seems to be very time consuming compared to the jobs.
I looked on the ebay and found that for less than $120 this www.ebay.ca/itm/382075467974 can be had.
All I would need to add would be a 1/2-13 threaded rod for a draw bar which I could get for about $5 from the local industrial fastener supply.
I never used collet holder previously. Is this going to be good enough for 1/1000" centering? That's all I can dream of with the mini lathe.