Hi Teresa,
It all depends on where you are going to go for your trip, some countries cost more than others.
I could get by with my own insulin (Aprida and Lanctus Injected), needles, test kit, strips on about 150 British Pounds a month.
I have though had to pay up to 500 British Pounds a month, so as mentioned before, do a little homework to the countries you decide to go and if one country is cheaper with supplies then buy, but again if you are going away on a 6 month break, then your local GP should prescribe you that amount to last you.
I also pay more than I need to, like I buy Libre 1 sensors from my part of the world and get them shipped to me, I am actually about to buy some UK ones this afternoon to send out to me, as they are Libre 2 and only going to cost me an extra 1 British Pound. What I am trying to say if you want to pay more then you can, just do some research before arriving in the country and see what is available there.
I do not need prescriptions, as I have lived here long enough, but costing and seeing a doctor to get a script should not cost that much, again depends on where your travelling.
If you use a pump, I am sorry I am not well versed on them and I would hazard a guess that in my part of the world they would be very far and between and only for the very wealthy of this country may have them.
I hope that helps a little and please follow your dreams, the world is a huge place and you will have some of the most amazing experiences, you can control your diabetes with just a little planning.
Thanks