Walmart offers Kryptonite Folding Bicycle Lock for $19.96 (reg $35) with free store pickup. 

Product Description:
The Kryptonite TKO Folding Lock is a modern, high-security lock, offering easy-to-use versatile locking functionality, all while folding up into an ultra-compact included carrying case for simple transport. Take advantage of the Key Safe program by registering your keys, allowing you to receive 2 free keys in the event that you misplace yours.

• Ultra compact and convenient locking shape
• Locking length: 2'9"
• Key Safe Program: Kryptonite will ship your first 2 keys for free, globally, in the event you lose them
• Carrying bracket included
• Lifetime Warranty
• Kryptonite Security Level 3