Orthotics either custom or "off the shelf" should be purchased with an intended goal. Some of the goals which do not make good orthotic purchases:
1- because of my insurance company covers me for them
2- my friend said I need them
3- I have fallen arches
4- they will help me in my high heels
These are common reasons why people then get sore feet. The main one is that "I have fallen arches". Most people actually do not have fallen arches, they have perfectly normal feet with an arch. A fallen arch is very noticeable, and actually not that common. Your feet may feel like they are fallen but usually they are not. This is a flat foot:
Nice example from:(http://www.alpinefootspecialists.com/diagnostic-procedures/custom-orthotics)
What you tend to find is that you are wearing poor shoes (most people do, even when shown that their shoes are poor they still disagree) for the activity that you want to do. One patient of ours wears their work shoes for a 2 mile walk...and they get foot pain.
Also note that footwear price and the right type of shoe is actually not in a relationship. A cheap pair of shoes can be as good as a expensive pair- it's the style you are after.
High heels are a very poor shoe in that they:
Having an expensive pair of high heels will still make that type of shoe poor. They are pretty tight as well so anything that gets put into your shoe will make it even tighter. Picture below from (https://en.wikipedia.org/wiki/File:J's_feet.jpg).
So getting a device for a pair of high heels because the ball of your foot hurts might not be the best treatment method.
That needs to be repeated again.
Most orthotics and inserts have some bulk to them and when placed into a shoe will reduce the depth and the width. This in turn creates less room for your foot and even making the orthotic painful and could easily rub your toes causing further pain and injury.
As said before, an orthotic should do something- or have a purpose. If you have foot pain then it can sometimes be because of an over exertion or a result of non-stretched muscles- plantar fasciitis is a common one.
Some feet just need cushioning- this is where a gel type of insert would help.
Orthotics come in a range of types and styles- but it depends upon who is using them. For example:
1- Runners and athletes would need an orthotic that is very flexible, have duration in materials and may have extra additions depending upon the assessment of the foot.
2- Patients who have arthritic feet can be given orthotics that manage the foot- are super soft and have pressure relieving materials. Also in this instance additional footwear- like running shoes, would have to be looked at so that an increase in shoe space would have a detrimental effect upon the feet.
3- Some people have cold feet and there are materials which can insulate the feet in times of coldness. These type of feet are usually thinner and additional cushioning would also have to be used.
Orthotics can be used as prevention and for deflection of pressure. Reduce the pressure away from an ulcer, a corn, reduce hard skin build up...and whole lot more.
Many companies offer these types of orthotics, they also offer a range of footcare products that just might suit your needs. They are all roughly similar to each other, just go with the brand that you know. But ultimately if you have painful feet, see a Podiatrist to make sure that your feet are OK.