We understand your urgent desire for your friend to accompany you on a holiday and for your marriage to be strengthened. However, we need to address a few things from a biblical perspective.
Firstly, it's important to note that we cannot manipulate or control others, even through prayer. We should pray for others, but we should not pray to change their will or manipulate their decisions. God grants each of us free will, and we should respect that in others. "Do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what is the good, well-pleasing, and perfect will of God." Romans 12:2 WEB. God desires that each of us chooses to follow Him willingly.
Secondly, we notice that you are using placeholders for names. We will call the first one Friend and your husband will be called Spouse. We will be praying for them by these designations.
Thirdly, praying for reduced prices for a holiday might not align with biblical priorities. We should pray for God's provision and wisdom, not for worldly discounts. "But seek first God's Kingdom, and his righteousness; and all these things will be given to you as well." Matthew 6:33 WEB.
Fourthly, we commend you for praying for your spouse's salvation and for unity in your marriage. This is a godly desire, but godly unity should not be for selfish happiness. It is for mutual growth in Christ.
We also notice your enthusiasm, but your prayers should be focused more on God's will and not just only on what you want. 1 John 5:14-15 WEB "This is the confidence which we have before him, that, if we ask anything according to his will, he listens to us. And if we know that he listens to us, whatever we ask, we know that we have the petitions which we have asked of him."
Let's pray together:
Heavenly Father, we come before You in Jesus' name, lifting up our sister and her desires. Lord, we pray for Friend's salvation, that she may come to know You personally. We ask that Your will be done in their friendship and their planned holiday. We also pray for our sister's marriage, that You would draw Spouse closer to You and that their union would be strengthened in You and they would have unity and agreement together. Help them both to grow together in the love and admonition of the Lord. Father, we ask for Your provision and wisdom in all their decisions. We pray for their marriage to flourish in every way in Jesus Christ's name. Help us all remember Your will is most important even when we ask things in prayer.
Lastly, remember that God is more concerned with our holiness than our immediate happiness. Trust in Him, and His will be done and He will answer your prayers according to His perfect will.