A clear order of purchase

The box first, because it roughly doubles the repertoire and needs no space or ceiling height. The pole second, because it costs very little and improves alignment feedback immediately. A proper mat third.

Everything after that is specialized, and buying it later — once you know how you actually train — wastes far less money than buying a bundle up front.

Accessory value ranking
AccessoryValueBuy when
Sitting boxHighestWith the machine or soon after
PoleHigh for the priceImmediately — it costs very little
Pilates matHighImmediately if you do mat work
Arc / spine correctorHigh if you sit all dayWithin the first year
JumpboardSituationalOnly with 8 ft ceilings
Magic circleModerateAnytime — inexpensive
Light weightsLowOnce alignment is reliable

Why bundles usually disappoint

Bundled packs are priced to look like savings, but they are assembled to move stock rather than to match how any individual trains. The common outcome is two useful items and three that stay in a cupboard.

Buying the box with the machine and everything else as you need it typically costs less in total and leaves you with nothing unused.

What almost nobody needs immediately

Jumpboards without the ceiling height, multiple ball sizes, weighted bars, and specialist straps beyond one good set. All of these have their uses and none of them belong in a first order.

The exception is if a teacher has specifically told you to get something — that is a reason, and a bundle is not.

The one thing worth deciding early

Whether you want a tower. Unlike every accessory here, a tower usually cannot be added to a machine that was not designed for it, so it is the one decision that has to be made at purchase rather than later.