The worldwide web is the best place to buy good quality safety wire for your aircraft. Take your pick from an oxidized or non-oxidized type. You can even buy a special canister to keep the wire for a long time.
Buying a few pieces of cut length each time you need the wire can be tiresome. It is better to buy a spool of wire for long-term use. Some online shops offer special canisters, which are recyclable for keeping spools of wire. Keeping the wire in a canister would protect the wire from corrosive substances.
Other than wire for your aircraft, you can also buy a good quality and easy to use communication device like Vertex radio online for use during your flights. There are various models, which comes with different features and sizes for your pick. The most important aspect of a radio communication device is its effectiveness when it comes to airborne communication.
You should be able to communicate clearly with the tower. Unclear communication can lead to a wrong decision, which could very well cost the lives of others. Imagine landing on the runaway when there is another aircraft landing at the same time. So, rather than taking a risk of using a low quality radio communication device, use a good quality device, which ensures effective and clear communication.