bptf bonus prices have little to do with what the item actually sells for. They are calculated by fixed multipliers (x6 for lvl 100) from the common price.

Without knowing what they actually do sell for, my advice would be:
If a deal sounds too good to be true, if often really isn't that good at all.
If you're not a collector and in doubt, do not take collector items. They can have a wide price range.

You may also want to have a look at his trade, if he has one, and see what offers he got already.

Going to agree with the above post about being cautious. A level 100 Vintage Vintage Merryweather is indeed worth quite a lot, especially to the right collector, but finding those people is very hard and most others will not consider paying anywhere close to a bud for it.

Thanks, everyone! I appreciate the advice

pain in the ass reselling "good" leveled vintage hats.

The value that tf.backpack gives to odd level vintages hats or weapons isn´t reliable at all that just an estimavite, tf.backpack says that a vintage ambassador is woth 8 keys, its almost impossible to sell it at even 6 keys.
I personally wouldnt do that deal.