Giant Size 1/day: 53,500 gp
Minute Form 1/day: 60,800 gp
Body Outside Body 1/day: 56,000 gp
But you already knew that. I imagine you are asking for opinions because those spells have a straight 1 Minute duration instead of a duration measured by 'per level' like most spells; except Body Outside Body with an odd duration of 1 per 2 levels.
But unless you personally want to change the rule, the Creating Magic Items chart is pretty explicit on what price modifiers based on spell duration it allows.
If a continuous item has an effect based on a spell with a duration measured in rounds, multiply the cost by 4. If the duration of the spell is 1 minute/level, multiply the cost by 2, and if the duration is 10 minutes/level, multiply the cost by 1.5. If the spell has a 24-hour duration or greater, divide the cost in half.
On that, however, this strictly applies to Continuous items. If your item has charges per day, it's part of the "Use-activated" side of the "Use-activated or Continuous" line on the Creating Magic Items chart and thus the little footnote does not apply at all.
Edit: Still putting my thoughts together kind of edit.
It'd be more appropriate to calculate the items based on the "Command Word" line of the chart instead though, thus reducing the above listed prices by...I unno, roughly 10k. Based on looking at the actual items used as examples for the two different Spell Effect items and how only the "Command Word" item example has Charges Per Day. Doing so also removes any question as to how to calculate the price as their is no footnote full of variable price modifiers attached to the "Command Word" price formula.