Make sure the seller is reliable.
Terra is a blockchain protocol that supports stable programmable payments and open financial infrastructure development. It is supported by a basket of fiat-pegged, seigniorage share style stablecoins which are algorithmically stabilized by its native cryptoasset, Luna.Learn more:
UST, EUT, BGT and others are stable coins stabilized by its native cryptoasset, Luna. You can easily swap these tokens between themselves or Luna right in the Terra Station app.
If you still hold only fiat money, you can buy Luna (or one of stables) on exchanges. Some of them may be hard to operate for a novice.