Like Guild Deception can be really strong, someone a while back joined the game and got to Mythic right away with a deck that was $4-8. It plays like a toolbox and can be pretty effective. Not S tier, but still pretty good.
Mill Deception with all the sleeps is extremely dangerous and difficult to counter if you don't have relic removal and they draw well. The overall win rates are not fantastic, but they seem to have a niche in the current meta.
Guild deception feels just too little of everything. its good for spamming cheap units. But, easily countered by war and nature that has ''random board damage'', bypassing hidden and order. It can reach high ranks, like all other decks, but it will be much harder than other higher ranked deck in my opinion.
As for Mill deception, I feel like it is a deserved ''bad'' tier. The relic is the only thing going on for the deck, and a deck built around 2/30 odds is weak. Plus, in the process of trying to draw the relic, you just end up giving insane value to the opponent.
also both going for cheap, I would recommend zombies, that are better and easier, or relic, which is much better but much harder, while both being in the under 10$ category.
Mill can counter aggro with sleeps and by the time the sleeps run out the opponent is dead from all the chip damage - in an ideal scenario. But I haven't played it much myself, this is just from what I see others do to me xD