God tells Hosea to take another adulteress as his wife to symbolise god's love of the Israelites despite all their failings. So he buys one for the bargain price of fifteen pieces of silver, and for an homer of barley, and an half homer of barley (v. 2). He makes sure to tell this one before the wedding that she shouldn't cheat on him, and promises to do the same. Then he explains that Israel will be without leadership for awhile, but then they'll go back to god.
God has decided to punish the Israelites in a totally new, unique way that has never been seen before: death, whoring and wine. People who worship Baal will be punished with harlot daughters and cheating wives. You know how divorced people say things like, 'I was married to X for 22 years, one of them happy?' That's what this entire book thus far reminds me of. There have been maybe 10 chapters total in which god wasn't punishing his chosen people for some transgression or another.
Even though Hosea falls well after the Babylonian exile in the Christian bible, he seems much more concerned with the sins of Ephraim and Judah, specifically whoring, which has resulted in strange children (v. 7). The punishment? Death by lions.
More threats of death against Ephraim and Judah for the sins of lewdness and whoredom. I'm sensing a theme.
Poor god! There he was, all ready to forgive the Israelites and start healing, but then stupid Ephraim had to come along and mess it all up by fraternising with foreigners. So now he has no choice but to punish them. How? You guessed it! Death.