you can look at the blockchain itself! there are millions of transactions from genesis block up to the current height. for that you could use a block explorer that lets you see the raw transaction hex, usually they all do but blockcypher may be the most convenient as it has a clickable button on each tx called "API call" that shows you both the hex and deserialized format.
example:
https://live.blockcypher.com/btc-testnet/tx/0e6931173d6bc63457b63d90fd8fc470d9b06c0bae79e354110466e47a062428/
=>
https://api.blockcypher.com/v1/btc/test3/txs/0e6931173d6bc63457b63d90fd8fc470d9b06c0bae79e354110466e47a062428?limit=50&includeHex=true
also i'd recommend using testnet, the coins don't have value so you can create transactions more freely without worry. and it is for "testing"!