With wireless prices creeping up, some phone users are reconsidering their options. That’s where promotional offers — like a new Costco and T-Mobile deal — come in.
Between June 18 and July 20, 2025, Costco members can receive up to $450 per line when switching to T-Mobile and activating a new device on eligible plans, according to Costco Insider’s preview of the retailer’s July Coupon Book.
That includes a $200 Costco Shop Card and a $250 Virtual Visa prepaid card for each qualifying line moved from select carriers like AT&T, Verizon, Spectrum, Xfinity Mobile, and others.
The incentives can add up for households with multiple lines. Depending on how many lines you switch, the promotion allows up to 12 $200 Shop Cards and 4 $250 Visa cards each, with a potential total value of $3,400.
This deal arrives as T-Mobile tries to win back customers after price hikes contributed to increased cancellations, according to its first-quarter 2025 earnings. Meanwhile, cable companies attracted nearly 900,000 new wireless customers in Q1 2025, reports MoffettNathanson.
But before jumping ship, here’s what to keep in mind — whether you shop at warehouse stores or not.
1. Evaluate total cost — not just the reward
A $450 offer may sound generous, but it doesn’t always mean real savings. Start by comparing your current plan’s monthly costs, data limits, and perks with what’s being offered.
If you’re using a prepaid or budget service — like Mint Mobile or Cricket — a switch might raise your monthly costs despite the one-time reward.
Also, check if the new plan requires purchasing a new phone or if you can bring your own. For Costco’s offer, you must activate a new device; bring your own device (BYOD) doesn’t qualify.
2. Understand the fine print
Costco’s offer is only available to new T-Mobile customers who switch from select carriers and activate eligible lines at a Costco wireless kiosk. You’ll need to show a current phone bill and ID to qualify. The offer doesn’t reimburse early termination fees, and there are limits on how many rewards you can receive per account.
Promotional conditions like these are common across the industry. Be sure to review:
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Minimum plan requirements
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Contract terms or installment agreements
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Whether you can stack the deal with other discounts
3. Think beyond the sign-up bonus
Some users switch carriers only to find weaker coverage or limited service in their area.
Before committing, research the provider’s network performance where you live, work, and travel. Sites like RootMetrics or carriers’ own coverage maps can help.
Also consider customer service quality and ease of account management. What’s convenient for some (e.g., in-person kiosk access) may be less relevant to others.
4. What else is out there?
Costco’s deal stands out for its high dollar amount, but it’s not the only option:
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Mint Mobile offers prepaid unlimited plans starting around $15/month with multi-month bundles.
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Cricket Wireless provides two unlimited lines for $65 and promotional deals on 5G phones.
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Spectrum Mobile offers unlimited plans around $30/month when bundled with broadband — and occasionally, a free year of mobile service.
These offers are subjected to change and often target different customer types — prepaid, multi-line, or bundle-savvy — so compare your usage and budget.
Ready to switch? Do the math first
Promotions can offer great value, but only if they fit your needs long-term. Run the numbers based on:
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Your expected data usage
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Total monthly bill after taxes and fees
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Whether you’ll owe money to your current carrier
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How long you plan to keep the new line active
Costco’s deal may work well for families switching several lines who shop regularly at the warehouse. But for others, the best plan might be to stick with what works, or explore a lower-cost provider with no big-name promo.
The bottom line? The $450 headline offer is genuine, but the real savings come from comparing the full picture, not just the up-front bonus.
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