Learn Portuguese (Portugal): A tatuagem tem um significado bonito.

While many Portuguese words ending in -m are masculine (like o som or o fim), words ending in the suffix -agem are almost always feminine. This is a very consistent rule to remember. Other common examples include a viagem (the trip), a mensagem (the message), and a coragem (the courage).

Could I use sentido instead of significado to say "meaning" here?

For a tattoo, significado is the best choice because it refers to symbolism, a specific definition, or a hidden message. While sentido can also translate to "meaning" or "sense," it is typically used for a physical sense, a direction, or to express if something is logical (as in não faz sentido, meaning "it makes no sense").

Does changing the word order to um bonito significado change the meaning?

It doesn't change the literal meaning, but it shifts the tone. Placing the adjective after the noun (significado bonito) is the standard, objective way to describe it. Placing it before the noun (bonito significado) makes the statement feel more poetic, emotional, and subjective. Varying your adjective placement like this is a great way to make your Portuguese sound more advanced.

If I wanted to add "even though it was expensive" to this sentence using se bem que, how would I do it?