Junior member's are pretty easy to obtain. You should rank them up then sell them.
not so easy mate, it takes 1.5++++ month to obtain

The only things worth selling/buying/collateral whatever are probably hero and sr member accounts.
buying junior member is very worthed mate
it only takes 1 week to ROI if enroll to sig camp
there are not many signatures campaigns which are activily accepting new members if it was alrready enrolled then maybe it would be worth it.