Any serious collector will take the day off, get in the car, puts the kids into care and raid the never-to-be-touched emergency savings account, and be there! With such a large and diverse collection there is likely to be more 'stuff' available than there are people prepared to do the above, and as such there are likely to be a few bargains, especially amongst the not so high profile items.
Looking at the 'prices realised' afterwards and wailing about how cheap this, that and the other was, is all too late!