Question: I'm working with a website that links into a Dynamics CRM Online. I'm new to both of these but find the best way to learn is to put yourself under pressure.

Anyway, I have the following LINQ query that I've built using LinqPad:

```cs
from m in py3_membershipSet
join c in ContactSet on m.py3_Member.Id equals c.ContactId 
where m.statuscode.Value == 1
orderby m.py3_name
select m

```

However, this gives an out of memory exception. It runs ok if I use Take(100) but I expect there to be about 1200 results to retrieve in total. Whether the memory issue is a LinqPad related problem I don't know but either way, I am assuming the above query isn't the most efficient way to pull these results.

I could really do with some help on making this more efficient, if it is as much of a memory hog as it appears via LinqPad.

Answer: 
You **cannot** use Google Play In-App Billing to make the user pay a custom price.

Moreover you cannot use Google Play In-App Billing to sell physical goods and services like journey tickets:

> 
> You can use In-app Billing to sell only digital content. You cannot use In-app Billing to sell physical goods, personal services, or anything that requires physical delivery. Unlike with priced applications, once the user has purchased an in-app product there is no refund window.
> 
> 
> 

<http://developer.android.com/google/play/billing/billing_overview.html>
Your use case perfectly fits the Google Wallet Instant Buy API for Android. Google Wallet Instant Buy API for Android is specifically for physical goods and services and has a simple integration into your Android App. It was launched during Google I/O 2013 and you can get an overview at the following blog post:

<http://googlecommerce.blogspot.com/2013/05/fast-and-easy-checkout-for-android-apps.html>

Also, please checkout the Google I/O Talk on the same topic 

<https://developers.google.com/events/io/sessions/330844794>

Since this is still in beta, if you're interested please sign up using the interest form 

<http://getinstantbuy.withgoogle.com/>