Twenty-three dollars? Pass.
The Destiny one is listed for $11.99, but yeah there isn't really much to gain with the other two.
The prices on Amazon are a lot lower than that - $14.69 for the newer two, and although the Destiny collection is not on .com yet, the price on .co.uk is £6.99 (viz. £8.99 for the other two). For comparison, Allegiance in Exile
, out at the same time, is $8.09/£4.99. Your e-book retailer may employ similar discounts.