Apple and iOS app developers have one of the biggest treats of the year so far. With many premium apps on sale for free, there are lots to choose from.

From a US$30 stock trading app to a campgrounds finder app, IBTimes Singapore has collected 10 amazing paid iOS apps from the App Store that you can download now for free.

Camping USA (US$1.99)

Find and reserve campgrounds and RV parks in any state in the US. Search camping locations by amenities like pets allowed, water, facilities, RV length and more.

Get Camping USA for iOS from the App Store.

Wonderoom (US$0.99)

Wonderoom is a full-featured, powerful photo editor with a clean interface designed for quick editing. It supports undo/redo, preserves EXIF data while editing, and it auto-saves your current progress so you can safely close the app and continue at any time.

Get Wonderoom for iOS from the App Store.

Hotstock (US$23.99)

Hotstock is the world's first artificial intelligence-powered stock trading application. Empowered by Watstock A.I., Hotstock can intelligently predict the market's top five winners each week. Hotstock predicts Friday's closing price on a weekly basis, so users will have access to these price predictions on every Monday when the market opens.

Get Hotstock for iOS from the App Store.

Week Calendar Widget Pro (US$1.99)

No need to unlock your device to see your calendar events. Week Calendar Widget Pro displays your existing calendar events from multiple calendar sources into one widget configurable view. Displays up to 7 days, tap on any day's header to go today view mode.

Get Week Calendar Widget Pro for iOS from the App Store.

Map Places (US$1.99)

Map Places allows you to find places from available categories. Pressing the selected category will display the number of hits on the map. Categories can also be saved to favourites. At the selected location, the information button can be navigated after the map selection.

Get Map Places for iOS from App Store.

Flow (US$4.99)

Overwhelmed by your mobile inbox? Flow presents your mail as a continuous feed, allowing you to review and act on your mail without ever losing context, and marking each mail as read when it is scrolled above mid-screen.

Tame your mobile inbox! Install on your iPhone today!

Get Flow for iOS from the App Store.

Simpler Pro (US$3.99)

Your address book is a mess? Simpler Pro will fix it in few seconds! Simpler Pro is a completely redesigned contacts app that makes your address book light, smart and user-friendly.

Get Simpler Pro for iOS from the App Store.

Smart Expense Manager (US$0.99)

Looking for an expense and budget tool? Stop searching. Smart Expense Manager is a simple, intuitive, stable and feature-rich app that is just designed for you. Everything you need at your fingertips to manage the expenditures, chequebook and budgets.

Get Smart Expense Manager for iOS from the App Store.

Synthesis+FX (US$1.99)

If you want to synthesize different photos into one photo, Synthesis+Fx will be your best choice. Without a complicated method of operations, you just need to choose the top and back photos simply, the new photo will be completed.

Get Synthesis+FX for iOS from the App Store.

Workout Timer-HIIT Tabata (US$3.99)

A handy application in which your workouts are accompanied by a LED flash, vibration and loud beeps. Fitness routine "Tabata" is a very intensive training. One cycle takes only 4 minutes. During this time you have time to do 8 exercises (20 seconds each) with short respites of 10 seconds.

Get Workout Timer for iOS from the App Store.

What are you waiting for? Get your iPhone or iPad and let the downloading spree begin!