What is it you're struggling with, when it comes to choosing some heels?
My only advice would be to avoid anything with complicated straps and buckles, so she can kick them off easily should she need to, and so they are less likely to snag lingerie/stockings.
As you're new, I'll also share the forum rules and photo guidlines with you, so you can take part in the community with confidence.
If you're not sure where to buy from, why not start simple and go with something from New Look or Primark? They usually have heels at reasonable prices :)
I know the wife has bought shoes online at Banana shoes, she loves the variety, up to 6inch + heels.
Was gonna sudgest Banana shoes too for exactly the same reason, my OH got some 6inch heels from there too! And they're a full 6inch heel, no platform! My OH loves them even though she does struggle a bit to walk in them but thats doesn't really matter in the bedroom!