(Improvement) Displaying postcard price in UI

[garatortiz]

• What is it? (leave one option)

  • (Improvement) of existing functionality

• Does it close any open issues? Closes #177

[coveralls]

Pull Request Test Coverage Report for Build 574

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.07%) to 81.164%

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Totals
Change from base Build 539:	-0.07%
Covered Lines:	1022
Relevant Lines:	1240

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💛 - Coveralls

[phahulin]

I had to move price variables to .env file, otherwise react can't find them (builds static htmls). Also fixed markup in few places.

[phahulin]

@fvictorio please re-review, I made changes based on your suggestions.

[fvictorio]

I removed the app.use for the register, that will be fixed in #179. I removed just that one to avoid future merge conflicts.