Learning a currency system and saving money in multiple currencies

No apologies for this post. I didn’t find the information for these questions I had before coming here in your forum, so I’m putting it in there to the next guy that comes here and I learn. 

Situation is this I left Colombia using the Colombian pesos into Panama using Panama currency into Dominican Republic today in Dominican Republic peso. All these use different conversion rates and I have $120 in the bank to make it until the end of the month after paying for this trip and bills so I am really pinching pennies in multiple currencies situation in Colombia is and you can say about because exchange rate is so high in Columbia you’ve got some slip. OK so about 20,000 Colombian pesos is a five dollar bill with that kind of exchange rate you have flexibility. Flew out of Columbia and into Panama. Checked exchange rate exchange rate is in Panama is higher than US dollar by one cent which means that the Panamanian peso whatever it is, is worth more than US dollar  I went to get a sandwich and the lady said $12 that means they’re in the US that sandwich was $12.30. I had to have the sandwich because I hadn’t had anything to eat so I got my sandwich and my soda and she said Veinte Cuatro so I paid 24 Panamanian units of currency on my credit card, which was about 24.50 in the US for that food then I fly here , the Dominican Republic immediately check the currency ratio and find that US dollar is more powerful in the DR. I went to the ATM to get some money out the only amount I could take out was 3000 pesos which translates to about US$53 that left me about $28 US dollars in my US bank account which gives me some back up for emergencies now I have type on screen  gonna charge you between two and three dollars US processing your account I said OK that’s not too much then it gave me an amount of 300 pesos I did the convergence it’s $5.40.   Here is what to take home from this.  when you can going from country to country check the currency regularly and take your time if you don’t have money to waste  and you’re being really tight, be careful check everything with the convergence rates on your phone because those are the ones that the bank is going to use. If you don’t do that you’re going to negotiate and you’re gonna still lose money because you won’t know what you’re talking about . Good luck. Leave me a message if I can help.