I just renewed my donation yesterday, I know there are many ways to do it. this is what I did... Downloaded the bitcoin (B in orange circle) wallet from google play on my smart phone. then, wallet settings >general>denomination and precision tap to choose to BTC, 8 decimal places and exit. your wallet is ready to receive and send bitcoins. this is how I buy 'em. I go to a bitcoin atm Machine (they are in malls and gas stations (Nova is very easy) once at bitcoin machine tap on "buy bitcoins" next on amount choose $1-999 no Id required. on next request your phone number to receive SMS code. enter code received and from three options choose "my wallet" or similar open your bitcoin wallet App on you phone and tap QR code top right corner to expand it and placed in front of the atm flashing scanner light once scanned, you'll see a message like "your bitcoins will be sent to a mix of digits like: 3Jmx4Tnlj9Mz.Which is your Wallet address equivalent a bank account. next, insert bills one by one lets say" 20,40 etc. and tap finish. the machine will start a short process then will offer a receipt showing the amount deposited, amountin bitcoins like BTC 0.00605124 and trasaction fee (about three dollars) and balance in dollars. sounds complicated but is very simple once you do it the first time it takes about two minutes.
Your concern about losing funds is my concern too!!! that's why I NEVER type the payee's bitcoin address manually. To receive, I always expand QR and scan to pay. We always have the options to enter manually or show QR. Let's say, I have to pay $15.00 in bitcoins, It will say sent to this address: Jx5MdzP9snR2jR9 (show QR) exactly BT O.00335120 If you type just ONE wrong digit you will have no idea who you sent the bitcoins to once you tap the sent button. I ALWAYS open the (show or expand QR) then when I open my wallet to send I tap on the little camera and scan the payee's QR barcode to always get the right address and proceed to enter the amount requested. Some websites even once you scan their barcode the amount to pay is already there, all you have to do is just press the sent or pay button. I hope this helps.